JP3893845B2 - Projection-type image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection-type image in which an image is formed on a screen by a reflective image display element having a plurality of micromirrors, that is, a micromirror display device, according to a video signal input to the micromirror display device. The present invention relates to a display device, and in particular, a projection-type image in which light utilization efficiency is improved in an apparatus configured to periodically separate white light into three primary colors using a rotating color filter and supply the light to a micromirror display device. The present invention relates to a display device.
[0002]
[Prior art]
Projection-type image display apparatus such as a projection television, which has a plurality of micromirrors and forms an image by modulating the light by controlling the angle of the micromirrors with respect to incident light according to an input video signal It has been proposed to be used. The micromirror display device is advantageous in that the set is more compact and lighter than the cathode ray tube, and the brightness linearity and contrast ratio with respect to the luminance signal are larger than those of the liquid crystal panel.
[0003]
As a conventional technology of a projection-type image display device using a micromirror display device, for example, a paper “DMD / DLP aimed at what is published in the December issue of the electronic magazine“ Electronics ”published by Ohm, Is known ”(by Marubun Co., Ltd., hereinafter referred to as prior literature). As introduced in this prior document, there are mainly two types of structures of the optical system of the micromirror display device.
[0004]
One is a so-called three-chip system using three micromirror display devices as shown in FIG. In this three-chip system, white light from a white light source is once separated into three primary colors of red, blue, and green by a color separation / combination prism, and modulated by three micromirror display devices corresponding to each of the three primary colors. The original image modulated and reflected by the display device is synthesized again and enlarged on a screen by a projection lens device to display a full color image.
[0005]
The other is called a one-chip system so as to use one micromirror display device as shown in FIG. This is because white light is periodically separated into three primary colors of red, blue and green by means of a disk-shaped rotating color filter, and the video signal for the three primary colors is synchronized with the rotation of the rotating color filter by one micromirror display device. Modulates in time division. Since this one-chip system uses only one micromirror display device, the optical system can be configured with a smaller number of parts than the above-described three-chip system, which is advantageous in terms of cost.
[0006]
[Problems to be solved by the invention]
However, the one-chip method, for example, displays red video (when supplying a red video signal to the micromirror display device), the blue and green light components of the luminous flux from the white light source are displayed. It is necessary to reflect the light by a rotating color filter so as not to enter the micromirror display device, and the light utilization efficiency is low in the three-chip system. In addition, when a white light beam is incident on the boundary of the rotating color filter, for example, a red filter portion that extracts red light and a blue filter portion that extracts blue light, the light that has passed through the rotating color filter is red and blue. Crosstalk occurs due to the inclusion of two colors. Therefore, during the period in which the white light beam spans two different color filter parts in the rotating color filter, the micromirror display device is turned off (the micromirror is tilted in a direction in which the reflected light does not face the entrance pupil of the projection lens). ) Is necessary. As this off time (hereinafter referred to as spoke time) increases, the light utilization efficiency further decreases.
[0007]
Accordingly, in order to shorten the spoke time and improve the light utilization efficiency in the one-chip micromirror display device optical system, the diameter of the white light beam incident on the rotating color filter is reduced to reduce the white light It is necessary to reduce the period during which the light beam spans the two color filter portions of the rotating color filter.
[0008]
Moreover, in order to improve the light utilization efficiency, it is also necessary to improve the capture rate of white light emitted from the light source. However, since the light source has a pair of electrodes disposed with a gap of a finite length, white light does not emit light from one central point of the light source. The emission points are distributed and aberration occurs. In order to improve the capture ratio of white light emitted from these emission points, a large-diameter reflecting mirror is required. However, if a large-diameter reflecting mirror is used, the convergence angle θ of the luminous flux increases, and the rotating color filter It is difficult to reduce the light spot diameter of the light beam incident on the. Further, the rotating color filter has a property that the spectral transmittance characteristic shifts to the short wavelength side when the incident angle of incident light increases. Therefore, when the convergence angle θ of the incident light with respect to the rotating color filter is increased, it is difficult to obtain a desired spectral transmittance characteristic, and the color purity is lowered.
[0009]
The present invention has been made in view of the above-described problems, and its object is to provide a light beam incident on a rotating color filter in a projection-type image display apparatus having a one-chip micromirror display device optical system. Is to reduce the spoke time to increase the light utilization efficiency and to increase the color purity to obtain a good image.
[0010]
[Means for Solving the Problems]
In order to achieve the object of the present invention, a projection-type image display apparatus according to the present invention includes a first reflecting mirror having an elliptical surface as a reflecting mirror of a light source in a one-chip micromirror display device optical system, A composite reflecting mirror having a second reflecting mirror having a spherical surface arranged on the light traveling direction side of the first reflecting mirror, and the light emitted from the light source by the first reflecting mirror and the second reflecting mirror The light reflected from the light is condensed and converged and incident on the rotating color filter.
[0011]
Specifically, the light source is disposed in the vicinity of the first focal point of the first reflecting mirror, and the second reflection is performed so that the center of curvature of the second reflecting mirror substantially coincides with the first focal point of the first reflecting mirror. A rotating color filter is disposed at the second focal point of the first reflecting mirror, which is separated from the first focal point in the light traveling direction, so that the minimum circle of confusion of the collected light beam is rotated. It is formed on top.
[0012]
The light that has passed through the rotating color filter may be incident on the image display device via multiple reflection element incidence having an opening shape similar to the shape of the effective display region of the image display device (micromirror display device). . Further, the order of the arrangement positions of the rotary color filter and the multiple reflection element is reversed, and the incident side opening of the multiple reflection element is arranged in the vicinity of the second focal point of the first reflecting mirror, The reflected light may be incident on the rotating color filter.
[0013]
According to such a configuration, since the minimum circle of confusion of the reflected light collected by the reflecting mirror can be reduced, the diameter of the reflected light beam formed on the rotating color filter can be reduced. Therefore, the spoke time can be shortened. As a result, the light utilization efficiency can be improved.
[0014]
In addition, a part of an illumination optical device including a light source, a reflecting mirror, a rotating color filter, a micromirror display device, and a projection lens that expands light modulated by the micromirror display device is provided at the lower end of the screen in the vertical direction If it is arranged so as to be positioned higher, the set can be made compact.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an optical system of a projection type image display apparatus according to an embodiment of the present invention.
[0016]
The white light emitted from the light source 2 is reflected by the first reflecting mirror 1 a having an elliptical reflecting surface and the second reflecting mirror 1 b having a spherical reflecting surface, and the light from the light source 2 is obtained as a convergent light beam 3. It is condensed in the axial direction. Since the first reflecting mirror 1a has an elliptical shape, it has two focal points. Here, the focal point closer to the first reflecting mirror 1a is called a first focal point, and the far focal point is called a second focal point. These first and second focal points are on the same axis (the optical axis of the light source), the light source is arranged so that the center of the light source 2 substantially coincides with the first focal point, and the center of curvature of the second reflecting mirror 1b. Also, the second reflecting mirror 1b is arranged so as to substantially coincide with the first focal point. In addition, a disc-shaped rotating color filter 4 that is rotated by a motor 5 is disposed in the vicinity of the second focal point.
[0017]
The white light emitted from the light source 2 travels toward the reflecting surface of the first reflecting mirror 1a, the reflecting surface of the second reflecting mirror 1b, and the optical axis direction, and reaches the reflecting surface of the first reflecting mirror 1a. The incident white light is reflected by the reflecting surface and travels toward the second focal point. On the other hand, the white light incident on the reflecting surface of the second reflecting mirror 1b is reflected by the reflecting surface and passes through the first focal point of the first reflecting mirror 1a, which is also the center of curvature of the second reflecting mirror 1b. The light enters the reflecting surface of the first reflecting mirror 1a, is reflected by the reflecting surface, and travels toward the second focal point. For this reason, most of the white light incident on the reflecting surfaces of the first reflecting mirror 1a and the second reflecting mirror 1b becomes a convergent light beam 3 and is collected at the second focal point of the first reflecting mirror 1a. A minimum circle of confusion of the convergent light beam 3 is formed in the vicinity of the second focal point. Therefore, a light spot having a diameter substantially equal to the diameter of the minimum circle of confusion of the convergent light beam 3 is formed on the surface of the rotating color filter 4.
[0018]
The rotating color filter 4 is for periodically separating the three primary color lights of red, blue, and green from the convergent light beam 3, and in the circumferential direction, for example, a red filter unit, a blue filter unit, and a green filter unit are provided. Sequentially arranged, the convergent light beam 3 is separated and selected in the order of red light, blue light, and green light according to the rotation of the motor 5 and emitted. Therefore, in practice, red, blue, and green images are switched and displayed on the screen. However, since the switching speed is high (approximately 120 Hz or more), the human eyes are alone. The three primary color images to be displayed are synthesized and appear as a full color image. As the rotating color filter 4, a plurality of red filter parts, blue filter parts, and green filter parts are used in order to increase the color separation (switching) speed and perform visual color synthesis satisfactorily. It is often done. In this case, red, blue, and green light are separated a plurality of times (cycles) while the rotating color filter 4 makes one round.
[0019]
The three primary color lights separated by the rotating color filter 4 are incident on the multiple reflection element 6. The multiple reflection element 6 is, for example, a rod lens or a hollow tetrahedron in which a metal thin film or a metal multilayer film is formed on the inner wall surface thereof. Therefore, the light beam separated into the three primary colors by the rotating color filter 4 is repeatedly subjected to multiple reflection inside thereof, thereby making the energy distribution of the light beam uniform and converting the shape of the light beam (substantially from a circle to a square). have. Further, the opening surfaces on the incident side and the emission side of the multiple reflection element 6 are rectangular and have a shape substantially similar to the effective display area of the micromirror display device 8. In other words, the aspect ratio of the aperture surface of the multiple reflection element 6 is substantially equal to the aspect ratio of the effective display area of the micromirror display device 8, and in this way, the light that has passed through the rotating color filter 4 can be efficiently passed. The micromirror display device 8 can be led. The light emitted from the multiple reflection element 6 enters the lens group 7 and is enlarged and corrected for aberrations. The lens group 7 includes, for example, a magnifying lens element 7a and a magnifying / aberration correcting lens element 7b. The light beam emitted from the multiple reflecting element 6 is magnified by the magnifying lens element 7a and further magnified / aberrated. Aberration correction is performed simultaneously with the enlargement by the lens 7b. Although not shown, the magnifying lens element 7a is configured to be movable in a direction orthogonal to its optical axis so that the irradiation position of the light emitted from the lens group 7 on the image display device can be adjusted. It may be. Further, the magnification / aberration correction lens element 7b may be configured to be movable along the optical axis direction so that the magnification ratio of the light emitted from the multiple reflection element 6 can be arbitrarily adjusted.
[0020]
The light that has passed through the lens group 7 enters a micromirror display device 8 that is an image display device including a plurality of micromirrors corresponding to each pixel, is reflected by the micromirror, and is emitted to a projection lens (not shown). Each of the plurality of micromirrors of the micromirror display device 8 has a reflection angle with respect to incident light controlled by a video signal input to the micromirror display device 8. When an image of a certain pixel is to be displayed, a control signal for controlling the reflection angle is output to the micromirror corresponding to the pixel. For example, when the control signal is “1”, control is performed so that the reflected light of the micromirror is guided in the direction of the projection lens. When the control signal is “0”, control is performed so that the reflected light is guided in a direction not incident on the projection lens. To do. In addition, in synchronization with the light separation operation of the rotating color filter 4, video signals corresponding to the three primary color lights of red, blue, and green are sequentially input to the micromirror display device 8 in a time division manner. That is, when the rotating color filter 4 separates red light, a red video signal is input to the micromirror display device 8, and when blue light is separated, a blue video signal is input.
[0021]
FIG. 2 is a diagram showing a second embodiment of the present invention. In the embodiment shown in FIG. 2, the positional relationship between the multiple reflection element 6 and the rotating color filter 4 in the embodiment shown in FIG. 1 is reversed. That is, in FIG. 1, the rotation color filter 4 and the multiple reflection element 6 are arranged in this order along the optical axis, but in FIG. 2, the multiple reflection element 6 and the rotation color filter 4 are arranged in this order along the optical axis. . In FIG. 1, the rotational color filter 4 is arranged closer to the light source 2 than the multiple reflection element 6 because the amount of light entering the incident-side opening surface of the multiple reflection element 6 is reduced to improve reliability due to light and temperature rise. In order to suppress the decrease, the configuration shown in FIG. 2 may be used as long as the reliability of the multiple reflection element 6 can be sufficiently ensured.
[0022]
Next, the function and effect of the composite reflecting mirror including the first reflecting mirror 1a having an elliptical reflecting surface and the second reflecting mirror 1b having a spherical reflecting surface, which are features of the present invention, will be described. .
[0023]
In the one-chip illumination optical apparatus using one micromirror display device 8, the following matters are important as described above in order to improve the light utilization efficiency. That is, (1) shortening the spoke time by reducing the diameter of the light beam incident on the rotating color filter, and (2) improving the capture rate of white light emitted from the light source (hereinafter referred to as the light beam capture rate). In order to improve the light flux capturing rate, for example, an elliptical reflecting mirror having a large aperture may be used as shown in FIG. However, when a reflector having a large aperture is used, the light beam concentration angle θ2 at the second focal point P0 increases, and it is difficult to reduce the diameter of the light beam incident on the rotary color filter. On the contrary, if an elliptical reflecting mirror having a small aperture is used, the light flux concentration angle θ1 at the second focal point P0 can be reduced, but the light flux capture rate is reduced.
[0024]
Therefore, in the present invention, as shown in FIG. 11, the first focal point of the first reflecting mirror 1a having an elliptical shape is arranged so that the center of curvature of the second reflecting mirror 1b having a spherical shape substantially coincides. The composite reflecting mirror configured as described above was used as the reflecting mirror of the light source 2. As a result, the following actions and effects are produced. (1) White light radiated in front of the light source 2 is captured by the second reflecting mirror 1b, returned to the reflecting surface of the first reflecting mirror 1a, and collected at the second focal point of the first reflecting mirror 1a. Since light can be emitted, the luminous flux capture rate is improved. (2) Even if the aperture of the first reflecting mirror 1a having an elliptical shape is reduced, the light flux capturing rate is improved, so that the light flux collecting angle θ1 at the second focal point of the first reflecting mirror 1a can be reduced. (3) Compared with the case where one elliptical reflecting mirror shown in FIG. 14 is used, the diameter of the reflecting mirror can be reduced and a compact illumination optical device can be realized.
[0025]
Further, according to the reflecting mirror of the present invention, the spot of the convergent light at the second focal point P0 can be made smaller even if the white light from the light source 2 has aberration. In the lamp used as the light source 2, as shown in FIGS. 9 and 10, the electrodes 15, 24, and 23 are not in close contact with each other and have a finite length gap. For this reason, it cannot be handled as a point light source. For example, even if a lamp having the configuration shown in FIG. 12 is arranged at the first focal point of the second reflecting mirror 1b, the second focal point is not condensed at one point and longitudinal aberration occurs. However, if the light beam condensing angle θ1 at the second focal point P0 is reduced as in the present invention, the longitudinal aberration is reduced, and the convergent light spot can be made smaller.
[0026]
Furthermore, if the light beam condensing angle is reduced, the following merits arise. This merit will be described with reference to FIG. FIG. 14 shows red (indicated by R in the figure), blue (indicated by B in the figure), green (indicated by G in the figure) used for the rotating color filter 4 of the one-chip illumination optical device using one micromirror display device. Display) Shows the general spectral transmittance characteristics of the filter unit corresponding to each color, and the solid line shows the characteristics when the light beam is incident on the color filter perpendicularly (incidence angle 0 °). . On the other hand, the broken line shows the state of the characteristic shift when the light beam enters the rotating color filter 4 from an oblique direction (with an incident angle). In general, the characteristic shift of the red filter portion having a longer wavelength is larger than that of the blue filter portion having a shorter wavelength. Therefore, the color purity of the three primary color lights extracted from the convergent white light by the rotating color filter 4 decreases as the variation in the incident angle of the light beam incident on the rotating color filter 4 decreases, and the degree becomes more conspicuous as the wavelength of light increases. become. That is, the color purity of monochromatic display is the worst for red light, followed by green light and blue light in this order. Therefore, if the light beam condensing angle is reduced, desired spectral transmittance characteristics can be obtained, and the color purity of a single color can be improved.
[0027]
As described above, according to the present invention, not only the minimum diameter of the light beam incident on the rotating color filter 4 can be made as small as possible, but also the light beam capture rate can be improved without increasing the aperture of the reflecting mirror. The luminous flux capture rate is improved by about 30% compared to the conventional elliptical reflector when the outer dimensions are the same. In addition, by adopting an elliptical and circular composite mirror, the convergence angle of the light beam can be reduced, so that good spectral transmittance characteristics can be obtained. In particular, the improvement effect becomes remarkable on the long wavelength side (red region), and the performance can be greatly improved. Therefore, according to the present invention, it is possible to realize a one-chip micromirror display device type projection type image display apparatus with low cost and high light utilization efficiency and color purity.
[0028]
Next, a lamp used as the light source 2 will be described. In the embodiment of the present invention, for example, an ultrahigh pressure mercury lamp is used as the light source 2. The ultra-high pressure mercury lamp includes an AC drive type and a DC drive type depending on the voltage applied to the electrodes. Since the polarity of the AC drive type lamp changes alternately, as shown in FIG. 9, the two electrodes have the same shape. The light quantity distribution around the electrodes generated at this time has a substantially symmetrical distribution between the two electrodes as shown in FIG. Furthermore, the light distribution is substantially symmetric with respect to an axis perpendicular to the line connecting the two electrodes (the line connecting 90 ° and 270 ° in FIG. 17). A virtual light source can be placed at the center between the electrodes. In the light distribution shown in FIG. 17, the light beam diverging in the range of 20 to 90 degrees and the light beam diverging in the range of 270 to 340 degrees are the second reflection of the composite reflector shown in FIG. The light is once reflected by the mirror 1b, passes through a virtual light emitting point 2 as indicated by 19 in FIG. 9, is reflected again by the first reflecting mirror 1a, and is condensed at the second focal point.
[0029]
On the other hand, as shown in FIG. 10, the direct-current drive type lamp has a shape in which the tip of the cathode 23 of the lamp tube is pointed so that electric discharge is likely to occur, and the tip of the anode 24 is rounder than the cathode. Tinged with For this reason, the light quantity distribution around the electrode is higher on the cathode side as shown in FIG. Further, the light distribution is an asymmetric distribution with respect to an axis perpendicular to the line connecting the two electrodes (the line connecting 90 ° and 270 ° in FIG. 18), and the amount of light distributed to the cathode side. There are many. For this reason, a high-efficiency illumination optical system can be realized by placing a virtual light source on the cathode side slightly from the center between the electrodes. As shown in FIG. 10, when the composite reflector is used, a condensing mechanism can realize an efficient illumination optical device by placing a virtual light source closer to the cathode side than the center between the electrodes. In the light distribution shown in FIG. 18, the luminous flux diverging in the range of 20 degrees to 90 degrees and the luminous flux diverging in the range of 270 degrees to 340 degrees are the second reflection of the composite reflecting mirror shown in FIG. The light is once reflected by the mirror 1b, passes through a virtual light emitting point 2 as indicated by 19 in FIG. 10, is reflected again by the first reflecting mirror 1a, and is condensed at the second focal point.
[0030]
Next, a specific example in which the configuration of the illumination optical apparatus according to the present invention described in FIGS. 1 and 2 is incorporated into an actual set will be described with reference to FIGS. FIG. 3 is a front view of the illumination optical apparatus according to the present invention, and in order to make it easy to understand the arrangement of each component of the illumination optical apparatus, a case member and a holder for holding or instructing each element. The members and lens barrels are shown as transparent. FIG. 4 is a side view of what is shown in FIG. Moreover, the description of the components having the same numbers as those shown in FIGS. 1 and 2 described above is omitted. In FIGS. 1 and 2, the light emitted from the first reflecting mirror 1a and the second reflecting mirror is directly incident on the rotary color filter 4, but in this specific example, the light reflected from the reflecting mirror is used. Is made to enter the rotating color filter 4 after being folded at a substantially right angle using the first folding mirror 12. Further, in FIGS. 1 and 2, the light that has passed through the magnifying lens element 7a and the magnifying / aberration correcting lens element 7b is directly incident on the micromirror display device 8, but in this example, The light that has passed through the magnifying lens element 7a and the magnifying / aberration correcting lens element 7b is folded at a substantially right angle using the second folding mirror 9 and then incident on the total reflection prism 10, and then incident on the total reflection prism 10 The light beam is narrowed down by a field lens (not shown) provided on the surface so as to enter the micromirror display device 8. The light incident on the micromirror display device 8 is modulated by the reflection of a dot unit by the video signal input to the micromirror display device 8 and is incident on the projection lens 11. As described above, when the micromirror of the micromirror display device 8 is in the on state, the reflection angle is controlled so that the reflected light is directed toward the incident position of the projection lens 11. On the other hand, when the micromirror is in the OFF state, the reflected light is controlled to be directed in a direction different from the position where the projection lens 11 is arranged so that the reflected light does not go to the incident position of the projection lens 11. The micromirror display device 8 expresses the brightness gradation by controlling the number of on / off times per unit time in accordance with the luminance component of the video signal.
[0031]
The projection lens 11 includes a plurality of lens elements, and functions to enlarge the reflected light from the micromirror display device 8 and project it onto the back surface of the screen disposed on the front surface of the set. Although not shown, the projection lens 11 has a specific lens element (lens element closest to the screen side (positioned closest to the light emission side)) among the plurality of lens elements, and is vertically moved along the optical axis of the projection lens 11. It is configured to be movable. In this configuration of movement, the lens barrel that holds the plurality of lens elements may be configured to have the first and second lens barrels. Specifically, the first lens barrel holds a specific lens element closest to the screen side, the second lens barrel holds a lens element other than the specific lens element, and the first lens. The lens barrel is configured to be movable on the optical axis with respect to the second lens element. Thereby, the enlargement ratio of the image displayed on the screen can be arbitrarily set.
[0032]
5 and 6 are external views when a cover or the like is attached to the illumination optical device shown in FIGS. FIG. 5 is a diagram of the illumination optical device as viewed from the front, and FIG. 6 is a diagram of the illumination optical device as viewed from above. Here, the illumination optical device is assumed to be 100. Various optical components described above are housed and held in the cover 13. The light source 2, the first reflecting mirror 1a, and the second reflecting mirror 1b are accommodated in the lamp house 14.
[0033]
FIGS. 7 and 8 show a state where such an illumination optical device 100 is incorporated in a projection image display device. The illumination optical device 100 is disposed at the bottom of a hollow space formed by the front cabinet 101 and the rear cabinet 103. A screen 102 on which light expanded by the projection lens 11 is projected from the back is attached to the front cabinet 101. As a result of considering the screen size (the size of the screen 102) as 50 inches with an aspect ratio of 16: 9 and the projection distance from the projection lens 11 to the screen 102 as 675 mm, to reduce the depth and height (compact) From the lower end of the screen 102, a part of the illumination optical device 100, that is, a part of the projection lens 11, the reflecting mirror, and the rotary color filter 4 constituting the illumination optical system is at a higher position (vertical direction of the screen).
[0034]
Next, for the purpose of enlarging the color reproduction region, the reinforcement by the red light emitting diode has been studied and will be described. Currently, the most efficient white light source is an ultra-high pressure mercury lamp. However, as is apparent from the spectral energy characteristics shown in FIG. 14, the spectral energy in the red region having a wavelength of 600 (nm) or more is smaller than that in the blue and green regions. For this reason, in the present invention, as shown in FIG. 19, a light emitting diode 28 for emitting red light is provided in the optical path of the illumination optical device to compensate for the above-described lack of energy of the lamp. The configuration of FIG. 19 is the same as that shown in FIG. 1 or 2 except for the light emitting diode 28. Therefore, detailed description thereof will be omitted. The red light emitted from the light emitting diode 28 enters the first reflecting mirror 1a and the second reflecting mirror 1b. Similarly to the white light emitted from the light source 2, the red light incident on the spherical reflecting surface of the second reflecting mirror 1b passes through the first focal point of the first reflecting mirror 1a and then passes through the first focus. The light is reflected on the elliptical reflecting surface of the reflecting mirror 1a and condensed on the second focal point. The red light incident on the elliptical reflecting surface of the first reflecting mirror 1a directly reaches the second focal point. Therefore, at the second focal point of the first reflecting mirror 1a, a spot of a light beam in which white light from the light source 2 and red light from the light emitting diode 28 are mixed is formed.
[0035]
As the light emitting diode 28 used for red reinforcement of the light source 2, for example, a high brightness red LED (TLRH190P) manufactured by Toshiba Corporation is included. This optical characteristic has a peak wavelength of 644 (nm), a luminance output of 15 (cd), and strong directivity. In addition, the emission spectrum has a wavelength range of relative emission intensity of 10% or more over the entire red region of 610 to 680 (nm), and by using one or a plurality of these, good characteristic improvement was obtained.
[0036]
【The invention's effect】
As described above, according to the present invention, a bright image with improved light utilization can be obtained in a projection image display apparatus using a one-chip optical system. In addition, it is possible to improve both the color purity and the light utilization efficiency, and a higher quality image can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view of an embodiment of an illumination optical apparatus according to the present invention.
FIG. 2 is a schematic view of another embodiment of an illumination optical apparatus according to the present invention.
FIG. 3 is a front view of the arrangement of components in the illumination optical apparatus according to the present invention.
FIG. 4 is a side view of the arrangement of each component in the illumination optical apparatus according to the present invention.
FIG. 5 is an external front view of an illumination optical apparatus according to the present invention.
FIG. 6 is an external side view of an illumination optical apparatus according to the present invention.
FIG. 7 is a front view of a projection-type image display device incorporating the illumination optical device according to the present invention.
FIG. 8 is a side view of a projection-type image display device incorporating the illumination optical device according to the present invention.
FIG. 9 is a diagram showing a main part of an AC drive type light source used in the present invention.
FIG. 10 is a diagram showing a main part of a DC drive type light source used in the present invention.
FIG. 11 is a diagram showing an example of a composite reflector used in the present invention.
FIG. 12 is a view showing an example of a reflecting mirror having an elliptical shape.
FIG. 13 is a characteristic diagram showing the spectral energy distribution of the light source used in the present invention.
FIG. 14 is a characteristic diagram showing the spectral transmittance of a rotating color filter used in the present invention.
FIG. 15 is a diagram showing a light amount distribution of an AC drive type light source used in the present invention.
FIG. 16 is a view showing a light amount distribution of a DC drive type light source used in the present invention.
FIG. 17 is a diagram showing a light distribution of an AC drive type light source used in the present invention.
FIG. 18 is a diagram showing a light distribution of a DC drive type light source used in the present invention.
19 is a diagram showing an example in which a light emitting diode is added to the embodiment shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a ... 1st reflective mirror, 1b ... 2nd reflective mirror, 2 ... Light source, 3 ... Light flux, 4 ... Rotation color filter 5 ... Multiple reflection element, 7a ... Enlargement lens element, 7b ... Enlargement / aberration correction lens Elements: 8 ... micromirror display device, 11 ... projection lens, 28 ... light emitting diode, 100 ... illumination optical device, 102 ... screen.

Claims (10)

A light source that emits white light, a reflecting mirror that reflects white light from the light source and guides the reflected light in an optical axis direction of the light source, light emitted from the light source and reflected light from the reflecting mirror A rotary color filter that periodically selects the incident light as R, G, or B primary color light, and guides the light that has passed through the rotary color filter to an image display device having a plurality of micromirrors, In a projection image display device configured to display an image by enlarging and projecting light modulated by an image display device on a screen by a projection lens,
The reflecting mirror includes a first reflecting mirror having an elliptical surface, and a second reflecting mirror having a spherical surface arranged on the light traveling direction side of the first reflecting mirror,
Placing the light source in the vicinity of the first focal point of the first reflecting mirror and the center of curvature of the second reflecting mirror;
By disposing the rotating color filter in the vicinity of the second focal point of the first reflecting mirror,
A light spot having a diameter substantially equal to the diameter of the minimum circle of confusion of the light beam reflected and converged by the first reflecting mirror and the second reflecting mirror is formed on the rotating color filter. A projection-type image display device as a feature.   2. The projection type image display apparatus according to claim 1, wherein the light that has passed through the rotating color filter is guided to the image display device through a multiple reflection element having a rectangular aperture shape.   The projection image display apparatus according to claim 2, wherein the multiple reflection element has an opening shape similar to an effective image display area of the image display device.   The projection image display apparatus according to claim 2, wherein the multiple reflection element is a rod lens.   The projection image display apparatus according to claim 2, wherein the multiple reflection element is a hollow tetrahedron having an inner wall surface provided with a metal thin film.   The light source has a pair of electrodes facing each other along the optical axis of the light source, and an intermediate point of the pair of electrodes and a first focal point of the first reflecting mirror are substantially matched. The projection-type image display device according to claim 1. When the light source is a direct current light source having an anode and a cathode facing each other along the optical axis of the light source,
The projection image display apparatus according to claim 1, wherein the first focal point of the first reflecting mirror is disposed on the cathode side with respect to an intermediate point between the anode and the cathode.   The projection image display according to claim 1, wherein the projection lens includes a plurality of lens elements and is configured such that a specific lens element interval can be changed according to a magnification of an enlarged image. apparatus. The illumination optical apparatus according to claim 8 , wherein the shape of the aperture hole on the light exit side of the projection lens is similar to the shape of the effective screen display area of the image display device.   A light emitting means for supplying red light is provided inside the reflecting mirror, and white light from the light source and red light from the light emitting means are mixed and condensed by the reflecting mirror. The projection type image display apparatus according to claim 1.

Images