JP2006064730A - Illuminating apparatus and projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately switch in a short time between the mode in which image quality takes priority and the mode in which brightness takes priority. <P>SOLUTION: The illuminating apparatus includes: a light source 1; a front color wheel and a rear color wheel 3, 4 through which light rays emitted from the light source 1 are passed in that order; and a control section 8 for switching the color wheels 3 and 4 between a first rotating state and a second rotating state. The front color wheel 3 and the rear color wheel 4 each have color filters for transmitting only light rays that have specific wavelength areas and white filters for transmitting all visible light rays, disposed such that the color filters alternate with the white filters in the direction of the rotation. In the first rotating state, both the color wheels 3 and 4 rotate having a positional relation so that light rays transmitted through the white filters of the front color wheel 3 are made incident on the color filters of the rear color wheels 4. In the second rotating state, only the front color wheel 3 rotates having a positional relation so that light rays transmitted through the color filters and white filters of the front color wheel 3 are made incident on the white filters of the rear color wheel 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection display device, and more particularly to a field sequential projection display device that performs color display in a time-division or color-sequential manner.

  In the field sequential projection display device, it is necessary to illuminate the light valve by separating the white light emitted from the light source into at least three primary color lights of red (R), green (G), and blue (B). In general, color separation is performed by a color wheel. The color wheel is a disk-shaped member in which color filters having different transmission characteristics are arranged along the circumferential direction. More specifically, along the circumferential direction, a red filter that transmits only light belonging to the red wavelength range, a green filter that transmits only light belonging to the green wavelength range, and only transmits light belonging to the blue wavelength range There is a disk-shaped member in which a blue filter to be disposed is arranged, and light emitted from the light source is guided onto a color wheel rotating in the circumferential direction. That is, each color filter of the color wheel sequentially traverses the optical path of the light emitted from the light source. As a result, the white light is separated into R, G, and B color lights in a time-sharing manner.

  As an example of a projection display device using the color wheel as described above, there is a sequential DMD video system disclosed in Patent Document 1. This system uses a color wheel to separate the light emitted from a light source, and a digital mirror device (with hundreds of thousands of mirror elements capable of controlling the individual tilt of each separated color light on a semiconductor memory cell) The image is displayed by irradiating DMD) and controlling the tilt of each mirror element to control the reflection state.

  Patent Document 2 discloses a projection display device using a color wheel in which a white filter not having wavelength selectivity is added in addition to the color filter having wavelength selectivity as described above. .

Further, Patent Document 3 discloses a projection display device in which two rotating color filters corresponding to the color wheel are arranged in an overlapping manner. Specifically, the first rotating color filter and the second rotating color filter are arranged so as to overlap each other on the optical path of the light emitted from the light source. Furthermore, as shown in FIG. 13A, only light belonging to the wavelength ranges of R, G, and B is selectively applied to the first rotating color filter 207 to which the light emitted from the light source first enters. Fan-shaped color filter pieces 201, 202, and 203 having a central angle of 120 ° for transmission are provided. On the other hand, as shown in FIG. 13B, the second rotating color filter 208 on which the light transmitted through the first rotating color filter 207 is incident does not transmit only the light belonging to the yellow wavelength region, that is, the yellow cut A filter 205 having a transmission characteristic of 90% or more with respect to light belonging to the visible light region is provided in the color filter piece 204 having the characteristics in the range of the central angle of 120 ° and the remaining 240 ° in the range. In the projection display device described in Patent Document 3, the combination of the color filter pieces through which light is transmitted is changed depending on the relative rotational position of the two rotary color filters 207 and 208 having the above-described configuration. Filter characteristics can be obtained.
JP-A-10-78550 JP 2000-152265 A JP 2003-98330 A

  As is apparent from the above description, in the field sequential projection display apparatus, the color of the displayed image depends on the characteristics of the color filter incorporated in the color wheel. Accordingly, in a projection display device (such as the projection display device described in Patent Document 1) having a color wheel composed only of color filters having wavelength selectivity, the purity of each color can be improved by narrowing the transmission band of each color filter. This can enhance the color reproducibility. However, when the transmission band of the color filter is narrowed, the amount of light decreases and the brightness of the image decreases.

  On the other hand, a projection display device including a color wheel to which a white filter not having wavelength selectivity is added in addition to the above color filter having wavelength selectivity (such as a projection display device described in Patent Document 2) ), The brightness of the image is improved, but the color reproducibility is deteriorated.

  In the projection display device described in Patent Document 3, the color wheel arranged at a position relatively close to the light source is composed of only a color filter having wavelength selectivity, and the relative rotation of the two color wheels is performed. Regardless of the position, the light emitted from the light source always passes through the color filter. Therefore, there is a problem similar to that of the projection display device described in Patent Document 1. The projection display device described in Patent Document 3 will be described in more detail as an example. If the color filter 205 of the second rotation color filter 208 shown in FIG. 13B is inserted in the optical path, the second rotation color will be described. A decrease in light amount due to transmission through the filter 208 is avoided. However, the light incident on the second rotating color filter 208 always passes through one of the color filter pieces 201, 202, and 203 of the first rotating color filter 207, and the amount of light has already decreased at this point. Therefore, no matter how the relative rotational positions of the first and second rotary color filters 207 and 208 are combined, the light quantity reduction in the projection display device having a color wheel composed only of color filters having wavelength selectivity is reduced. The problem is not solved. Furthermore, in order to increase the purity of each color, if the transmission band of the color filter pieces 201, 202, 203 of the first rotating color filter 207 shown in FIG. This is the same as that of a projection display device having a color wheel composed only of a color filter having a characteristic.

  An object of the present invention is to realize a projection display device capable of accurately switching between an image quality-oriented mode and a brightness-oriented mode in a short time.

  The illumination device of the present invention includes a light source, a front color wheel on which light emitted from the light source is incident, a rear color wheel on which light transmitted through the front color wheel is incident, and a rotation state of the front color wheel and the rear color wheel. Control means for switching between a first rotation state and a second rotation state, and the front color wheel and the rear color wheel include a color filter that transmits only light belonging to a predetermined wavelength range, and a wavelength range. And a white filter that transmits all visible light alternately along the rotation direction, and in the first rotation state, the light is transmitted through the white filter of the preceding color wheel and is incident on the color filter of the subsequent color wheel. Both of the two color wheels rotate while maintaining the color, and in the second rotation state, the color filter and white filter of the preceding color wheel Transmitted light only front color wheel while maintaining the positional relationship that is incident on the white filter of the subsequent color wheel rotates. Therefore, when the front and rear color wheels are in the first rotation state, only R, G, and B color lights are output, and no white light is output. On the other hand, when the front and rear color wheels are in the second rotation state, in addition to the R, G, and B color lights, unseparated light (white light) that is not separated by any of the front and rear color wheels. Is output. Therefore, if the rotation state of the front and rear color wheels is switched to the first rotation state, illumination with light with higher color purity is possible, and if the rotation state is switched to the second rotation state, illumination with brighter light is possible. Is possible. Furthermore, it is not necessary to physically move or replace the color wheel in order to switch the characteristics of the illumination light as described above.

  A red filter that transmits only light that belongs to the red wavelength range, a green filter that transmits only light that belongs to the green wavelength range, a blue filter that transmits only light that belongs to the blue wavelength range, and a wavelength. A white filter that transmits all visible light regardless of the wavelength range is provided, and a color filter having a transmission wavelength range different from that of the red, green, and blue filters, and all visible light is transmitted regardless of the wavelength range. In the first rotation state, the light passing through a part of the white filter provided in the front color wheel is incident on the color filter provided in the rear color wheel while maintaining the positional relationship between the two. Both the color wheel is rotated, and in the second rotation state, the color filter and the white filter provided in the preceding color wheel Transmitted light can also be rotated only front color wheel while maintaining the positional relationship that is incident on the white filter disposed downstream color wheel. Accordingly, when the rotation state of the front and rear color wheels is switched to the first rotation state, light in a wavelength region that cannot be extracted only by the front color wheel is added, and the color reproducibility is enhanced.

  The projection display device of the present invention modulates the light output from the illumination device of the present invention with a light valve to form image light, and projects the formed image light through a projection lens. Therefore, a display mode in which image quality is more important than brightness and a display mode in which brightness is more important than image quality can be accurately switched in a short time.

  According to the present invention, it is possible to realize a projection display device that can accurately switch between an image quality-oriented mode and a brightness-oriented mode in a short time.

(Embodiment 1)
Hereinafter, an example of an embodiment of the projection display device of the present invention will be described in detail. FIG. 1 is a schematic diagram showing the overall configuration of a projector that embodies the projection display device of the present invention. The projector includes a light source 1, a condenser lens 2, a front color wheel 3, a rear color wheel 4, an integrator rod 5, a collimator lens 6, and a detection unit 7 for detecting the positional relationship between the front and rear color wheels 3 and 4. The illumination device 10 includes a control unit 8 that switches the rotation state of the front and rear color wheels 3 and 4, a TIR prism 20, a light valve (DMD 30), and a projection lens 40.

  The light source 1 is a discharge lamp that emits white light, such as a metal halide lamp, a xenon lamp, or a high-pressure mercury lamp. A reflector 50 having an elliptical reflecting surface is disposed around the light source 1, and light emitted from the light source 1 is reflected by the reflecting surface of the reflector 50 and enters the condenser lens 2. The light source 1 and the reflector 50 are generally unitized, but may be separate. The condenser lens 2 collects the incident light and makes it incident on the preceding color wheel 3. The front-stage color wheel 3 and the rear-stage color wheel 4 are arranged forward and backward along the optical path of the light emitted from the condenser lens 2 so that light passes through the front-stage color wheel 3 and the rear-stage color wheel 4 in this order. .

As shown in FIG. 2 (a), the front stage color wheel 3 has a disk shape, a substantially fan-shaped red filter 60 that selectively transmits only light belonging to the red wavelength range, and a green wavelength range. A substantially fan-shaped green filter 61 that selectively transmits only light belonging thereto and a substantially fan-shaped blue filter 62 that selectively transmits only light belonging to the blue wavelength range are provided along the circumferential direction. Between the 60, 61 and 62, there are arranged substantially fan-shaped white filters 63, 64 and 65 that transmit all visible light regardless of the wavelength range. That is, the color filters 60, 61, 62 and the white filters 63, 64, 65 are alternately arranged. Here, the center angle θ ₁ of the red filter 60 is 118 °, the center angle θ ₂ of the green filter 61 is 105 °, and the center angle θ ₃ of the blue filter 62 is 85 °. The center angle θ ₄ of the white filter 63 disposed between the red filter 60 and the green filter 61 is 17 °, and the center angle θ ₅ of the white filter 64 disposed between the green filter 61 and the blue filter 62 is. Is 17 °, and the central angle θ ₆ of the white filter 65 disposed between the blue filter 62 and the red filter 60 is 18 °. In FIG. 3, the transmission spectrum of each color filter 60, 61, 62 is shown. In the figure, the chain line indicates the transmission spectrum of the red filter 60, the alternate long and short dash line indicates the transmission spectrum of the green filter 61, and the solid line indicates the transmission spectrum of the blue filter 62. Moreover, the white filters 63, 64, and 65 exhibit a transmittance of 98% or more with respect to light in the visible light range.

As shown in FIG. 2B, the rear stage color wheel 4 has the same shape as the front stage color wheel 3, and a red filter 70, a green filter 71, and a blue filter 72 are provided along the circumferential direction. White filters 73, 74, and 75 are disposed between the filters 70, 71, and 72. The red filter 70, the green filter 71, the blue filter 72, and the white filters 73, 74, 75 provided in the rear stage color wheel 4 have the same transmission characteristics as those provided in the front stage color wheel 3. However, the center angles θ ₇ and θ ₈ of the red filter 70 and the green filter 71 of the rear stage color wheel 4 are 17 °, and the center angle θ ₉ of the blue filter 72 is 18 °. On the other hand, the central angle θ ₁₀ of the white filter 73 disposed between the red filter 70 and the green filter 71 is 105 °, and the central angle θ ₁₁ of the white filter 74 disposed between the green filter 71 and the blue filter 72. Is 85 °, and the central angle θ ₁₂ of the white filter 75 disposed between the blue filter 72 and the red filter 70 is 118 °. That is, in the front color wheel 3 and the rear color wheel 7, the ratio of the color filter and the white filter is opposite.

  Referring again to FIG. 1, the rotary shafts (not shown) of motors 80 and 81 that are driven and controlled by the control unit 8 are connected to the front and rear color wheels 3 and 4, respectively. Is rotated in the circumferential direction. The rotation position of the front and rear color wheels 3 and 4 is detected by the detection unit 7. Based on the detection result of the detection unit 7, the control unit 8 grasps the relative rotational positions of the two color wheels 3, 4 and then controls the motors 80, 81 to control the front and rear color wheels 3, 4 to a predetermined level. Rotate. The rotational state of the front and rear color wheels 3 and 4 will be described in detail later.

  The integrator rod 5 is a long and narrow prismatic optical glass along the traveling direction of the light emitted from the rear color wheel 4. The light emitted from the rear stage color wheel 4 enters from one end face in the longitudinal direction of the integrator rod 5, travels while totally reflecting inside the rod 5, and exits from the other end face. In the meantime, the luminance distribution in the light beam cross section orthogonal to the optical axis is made uniform. The light whose luminance distribution is made uniform is collimated by the collimating lens 6 and enters the total reflection prism (TIR prism 20).

  The TIR prism 20 converts the optical path of the light emitted from the collimating lens 6 and makes it incident on the DMD 30 and transmits the light (image light) reflected by the DMD 30 as it is. The image light transmitted through the TIR prism 30 enters the projection lens 40 and is enlarged and projected through the lens 40 toward a screen (not shown).

  Next, the rotation state of the front and rear color wheels 3 and 4 will be described in detail. The rotation states of the front and rear color wheels 3 and 4 include at least two types of rotation states of a first rotation state and a second rotation state, and the rotation state is switched by the control unit 8 shown in FIG. The first rotation state is a rotation state when the image quality (color) is more important than the brightness of the image, and the second rotation state is a rotation state when the brightness is more important than the image quality.

In the first rotation state, the white filter 63 of the front color wheel 3 shown in FIG. 2A and the red filter 70 of the rear color wheel 4 shown in FIG. 64 and the green filter 71 of the rear stage color wheel 4 are overlapped, and the white color filter 65 of the front stage color wheel 3 and the blue filter 72 of the rear stage color wheel 4 are maintained, and the front and rear stage color wheels 3, 4 are maintained. Both rotate. That is, the white filter 63 and the red filter 70 simultaneously traverse the optical path, the white filter 64 and the green filter 71 simultaneously traverse the optical path, and the white filter 65 and the blue filter 72 simultaneously traverse the optical path. Here, the white filters 73, 74, and 75 of the latter-stage color filter 4 can be optically ignored. Therefore, when the front and rear color wheels 3 and 4 are in the first rotation state, the light transmitted through the color wheels 3 and 4 is red filter R having a central angle θ _r of 135 ° as shown in FIG. Is equivalent to light transmitted through a three-segment color wheel provided with a green filter G having a central angle θ _g of 122 ° and a blue filter B having a central angle θ _b of 103 °. As a result, the brightness of the image is inferior to that in the second rotation state described later, but the color is remarkably improved and a high-quality image is displayed.

  On the other hand, in the second rotation state, any one of the white filters 73, 74, and 75 provided on the rear stage color wheel 4 shown in FIG. 2B is on the optical path of the light transmitted through the front stage color wheel 3. The inserted state is fixed, and only the front color wheel 3 is rotated. At this time, optically the latter color wheel 4 can be ignored. Accordingly, when the front and rear color wheels 3 and 4 are in the second rotation state, the light transmitted through the color wheels 3 and 4 is equivalent to the light transmitted through only the front color wheel 3. As a result, a brighter image is displayed although the image quality is inferior to that in the first rotation state.

  Next, the configuration of the detection unit 7 necessary for accurately switching between the first rotation state and the second rotation state will be described. As shown in FIG. 1, the detection unit 7 includes a white LED 90 as an alignment light source, a wavelength selection filter 91 that selectively blocks light belonging to a blue wavelength range, and a PIN photodiode (hereinafter referred to as a light receiving element). "Photodiode 92"). Further, the components of these detection units 7 are such that light emitted from the white LED 90 passes through the front and rear color filters 3 and 4 and enters the wavelength selection filter 91, and the light transmitted through the wavelength selection filter 91 is a photodiode. 92 so as to receive light.

  FIG. 5 shows a transmission spectrum of the wavelength selection filter 91. 6A to 6C schematically show the output of the photodiode 92 when the front and rear color wheels 3 and 4 are in the first rotation state. 6A shows a case where the light received by the photodiode 92 is transmitted through the front stage color wheel 3 and the wavelength selection filter 92, and FIG. 6B shows a case where the light transmitted through the rear stage color wheel 4 and the wavelength selection filter 91. (C) shows a case where the light passes through the front and rear color filters 3 and 4 and the wavelength selection filter 91, respectively. As shown in FIG. 3, since the light transmitted through the color filters of the front and rear color wheels 3 and 4 has a spectrum that does not overlap each other, the light transmitted through the front and rear color wheels 3 and 4 is illustrated. When the photodiode 92 receives light through the wavelength selection filter 91 having the transmission characteristics shown in FIG. 5, the light is transmitted to both the front and rear color wheels 3 and the rear color wheel 4 or one of the blue filters 62 and 72 (FIG. 2). The output of the photodiode 92 becomes the lowest (nearly zero) only when the light is transmitted through. Precisely, the output of the photodiode 92 is determined by the sensitivity of the photodiode 92 with respect to the band and wavelength of the received light, so that the rectangular output as shown in FIGS. Here, since it is important that the output of the photodiode 92 is minimized when the light transmitted through the blue filters 62 and 72 is received, it is simply shown.

  As can be seen from FIGS. 6A to 6C, when the rotation state of the front and rear color wheels 3 and 4 is in the first rotation state, the time when the output of the photodiode 92 is the lowest (TB12). ) Is the longest. On the other hand, as shown in FIGS. 7A to 7C, when the rotation state of the front and rear color wheels 3 and 4 deviates from the first rotation state, that is, the blue color of the front color wheel 3 and the rear color wheel 4. When the filters 62 and 72 are partially overlapped, the time (TB12) is shorter than that in the case shown in FIG. Therefore, when the first rotation state is selected, the control unit 8 shown in FIG. 1 monitors the output of the photodiode 92, so that the time (TB12) during which the output is the lowest is the longest. The motors 80 and 81 which are driving sources of the color wheels 3 and 4 are controlled. As described above, the first rotation state is reliably realized and maintained.

  On the other hand, in order to set the front and rear color wheels 3 and 4 to the second rotation state, any of the white filters 73, 74 and 75 (FIG. 2B) of the rear color wheel 4 is inserted in the optical path. Therefore, high-accuracy alignment as in the case of realizing the first rotation state is not required. Therefore, it is sufficient to detect the rotational state by a method conventionally used for detecting the rotational position of the color wheel. For example, a reflecting piece is provided on the rotating shaft of the second color wheel 4, and light emitted from the light emitting element is irradiated to the reflecting piece through a sensor unit in which the light emitting element and the light receiving element are integrated, and reflected by the reflecting piece. It is installed at a position where the received light is received by the light receiving element.

  As described above, in the projection display device of this example, the image quality-oriented mode and the brightness-oriented mode can be switched instantaneously and accurately by switching the rotation state of the front and rear color wheels 3 and 4. Can do.

  As a method of switching between the image quality emphasis mode and the brightness emphasis mode, prepare color wheels for the image quality emphasis mode and the brightness emphasis mode separately, and replace the color wheel inserted into the optical path as necessary. In addition, a filter area for the image quality emphasis mode and a filter area for the brightness emphasis mode are provided in one color wheel, and the filter area inserted into the optical path is switched by displacing the color wheel. It is also possible. However, since these methods involve displacement of the color filter, there are disadvantages such as optical axis misalignment and stray light generation. Although a method of detecting the rotational position of the front and rear color wheels with an encoder is also conceivable, there is a demerit that necessary members are large and expensive.

(Embodiment 2)
Hereinafter, another example of the embodiment of the projection display device of the present invention will be described in detail. The basic configuration of the projection display apparatus of this example is the same as that of the projection display apparatus described in the first embodiment. Only the configuration of the lighting device is different. Specifically, the configurations of the color wheel and the detection unit of the illumination device are different from those described in the first embodiment.

  The illumination device provided in the projection display device of this example also includes front and rear color wheels. The filter configuration of these color wheels includes a front color wheel 3 and a rear color wheel 4 shown in FIGS. Is different. FIG. 8A shows a front color wheel included in the lighting device in this example, and FIG. 8B shows a rear color wheel.

The front color wheel 103 shown in FIG. 8A is provided with a substantially fan-shaped red filter 110, a green filter 111, a white filter 112, and a blue filter 113 along the circumferential direction. The transmission characteristics of the color filters 110, 111, and 113 are the same as those of the red filter 60, the green filter 61, and the blue filter 62 shown in FIG. 2A, and the details are as shown in FIG. Further, the transmission characteristics of the white filter 112 are the same as those of the white filters 63, 64, and 65 shown in FIG. Further, the center angle θ ₂₀ of the red filter 110 shown in FIG. 8A is 96 °, the center angle θ ₂₁ of the green filter 111 is 88 °, the center angle θ ₂₂ of the white filter 112 is 94 °, and the center of the blue filter 113. The angle θ ₂₃ is 82 °.

The rear stage color wheel 104 shown in FIG. 8B has a color filter (yellow filter 114) having a central angle θ ₂₄ of 47 °, and the other part is a white filter 115 having the same transmission characteristics as the white filter 112. It is configured. The yellow filter 114 shows the same transmission spectrum as that shown in FIG.

  Also in the projection display apparatus of this example, in the second rotation state in which the brightness of the image is regarded as important, the rear color wheel 104 shown in FIG. 8B is replaced with the white filter 115 shown in FIG. 8A. It fixes in the state inserted in the optical path of the light which permeate | transmitted the color wheel 103, and only the front | former stage color wheel 103 is rotated. At this time, the latter stage color wheel 104 can be ignored optically. Accordingly, when the front and rear color wheels 103 and 104 are in the second rotation state, the light transmitted through these color wheels 103 and 104 is equivalent to the light transmitted through only the previous color wheel 103. As a result, although the relative image quality is inferior, the brightness is remarkably improved and a high-luminance image is displayed.

On the other hand, in the first rotation state in which image quality is emphasized, the boundary line 120 between the green filter 111 and the white filter 112 in the front color wheel 103 and the boundary between the yellow filter 114 and the white filter 115 in the rotation direction of the rear color wheel 104. The line 121 overlaps, and immediately after the green filter 111 of the front color wheel 103 passes through the optical path, both the front and rear color wheels 103 and 104 maintain the state in which the yellow filter 114 of the rear color wheel 104 enters the optical path. It rotates in conjunction. At this time, a part of the white filter 112 of the front color wheel 103 overlapping the yellow filter 114 of the rear color wheel 104 can be optically ignored. Accordingly, when the front and rear color wheels 103 and 104 are in the first rotation state, the light transmitted through the color wheels 103 and 104 is red filter R having a central angle θ _r of 96 ° as shown in FIG. A green filter G having a central angle θ _g of 88 °, a yellow filter Y having a central angle θ _y of 47 °, a white filter W having a central angle θ _w of 47 °, and a blue filter having a central angle θ _b of 82 °. This is equivalent to light transmitted through a five-division color wheel provided with a filter. As a result, the relative brightness of the image is inferior because the ratio of the white filter W is reduced as compared with the second rotation state. However, since the yellow filter Y is added, the yellow component is added, the color space is expanded, and the color reproducibility is improved.

  However, if the yellow filter 114 shown in FIG. 8B is replaced with another color filter having different transmission characteristics, a desired color can be added. In short, the transmission characteristics of the color filter arranged at the position of the yellow filter 114 shown in FIG. 8B can be appropriately determined depending on the balance between the characteristics of the previous color wheel 103 and the color component to be added. .

  Next, the detection part with which the illuminating device in this example is provided is demonstrated. As in the first embodiment, the detection unit is composed of a white LED as a light source for alignment, a wavelength selection filter, and a PIN photodiode as a light receiving element. It is the same. However, the wavelength selection filter has a characteristic of selectively transmitting only light belonging to the blue wavelength region. Specifically, it has the same transmission characteristics as the blue filter 113 of the preceding stage color wheel 103 shown in FIG.

  10A to 10C schematically show the outputs of the photodiodes when the front and rear color wheels 103 and 104 are in the first rotation state. 10A shows the case where the light received by the photodiode is transmitted through the front color wheel 103 and the wavelength selection filter, and FIG. 10B shows the case where the light transmitted through the rear color wheel 104 and the wavelength selection filter. , And (c) show cases where the light passes through the front and rear color filters 103 and 104 and the wavelength selection filter, respectively. As can be seen from FIGS. 10 (a) to 10 (c), since a blue filter is used as the wavelength selection filter, only when a blue component is included in the light transmitted through the color wheels 103 and 104 at the front and rear stages, There is a diode output. Therefore, when the front and rear color wheels 103 and 104 are in the first rotation state, the time (TB12) when the output of the photodiode is not zero is the shortest (FIG. 10C).

  On the other hand, when the yellow filter 114 of the rear stage color wheel 104 partially overlaps the green filter 111 of the front stage color wheel 103, the light reception time of the light transmitted through the white filters 112 and 115 is extended by the overlap amount. The time (TB12) becomes longer (FIG. 11). Conversely, when the yellow filter 114 of the rear stage color wheel 104 shifts to the blue filter 113 side of the front stage color wheel 103, the green filter 111 of the front stage color wheel 103 passes through the optical path, and then the yellow filter 114 of the rear stage color wheel 104 passes through the optical path. If a time lag occurs before entering, the output of the photodiode in one cycle is separated into two (FIG. 12).

  Therefore, if the relative positional relationship between the front and rear color wheels 103 and 104 is controlled so that the time when the output of the photodiode is not zero (TB12) is the shortest and the output is not separated into two, the first The rotation state is reliably realized and maintained.

1 is a schematic diagram illustrating a configuration of a projection display device according to Embodiment 1. FIG. (A) is a schematic diagram which shows the filter structure of the front | former stage color wheel shown in FIG. 1, (b) is a schematic diagram which shows the filter structure of a back | latter stage color wheel. It is a figure showing the transmission spectrum of each color filter shown to Fig.2 (a). It is a schematic diagram which shows the substantial filter structure when the color wheel of the front and back stage shown to Fig.2 (a) (b) exists in a 1st rotation state. It is a figure showing the transmission spectrum of the wavelength selection filter shown in FIG. (A)-(c) is a figure which shows the output of a photodiode when the color wheel of the front and back stage shown to Fig.2 (a) (b) is in a 1st rotation state. (A)-(c) is a figure which shows the output of a photodiode when the color wheel of the front and back stage shown to Fig.2 (a) (b) remove | deviates from the 1st rotation state. (A) is a schematic diagram which shows the filter structure in the front | former color wheel of the illuminating device with which the projection display apparatus which concerns on Embodiment 2 is equipped, (b) is a schematic diagram which shows the filter structure of a back | latter stage color wheel. It is a schematic diagram which shows the substantial filter structure when the color wheel of the front and back stage shown to Fig.8 (a) (b) exists in a 1st rotation state. (A)-(c) is a figure which shows the output of a photodiode when the color wheel of the front and back stage shown to Fig.8 (a) (b) is in a 1st rotation state. It is a figure which shows an example of the output of a photodiode when the color wheel of the front and back stage shown to Fig.8 (a) (b) remove | deviated from the 1st rotation state. It is a figure which shows the other example of the output of a photodiode when the color wheel of the front and back stage shown to Fig.8 (a) (b) remove | deviated from the 1st rotation state. (A) is a schematic diagram which shows the filter structure of the 1st rotation color filter described in patent document 3, (b) is a schematic diagram which shows the filter structure of a 2nd rotation color filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Condensing lens 3,103 Front | former stage color wheel 4,104 Back | latter stage | wheel color wheel 5 Integrator rod 6 Collimating lens 7 Detection part 10 Illuminating device 20 TIR prism 30 DMD
40 Projection lens 50 Reflector 60, 70, 110 Red filter 61, 71, 111 Green filter 62, 72, 113 Blue filter 63, 64, 65, 73, 74, 75, 112, 115 White filter 80 Motor 81 Motor 90 White LED
91 Photodiode 114 Yellow filter 120, 121 Boundary line

Claims (8)

A light source;
A pre-stage color wheel on which light emitted from the light source is incident;
A rear color wheel on which light transmitted through the front color wheel is incident;
Control means for switching the rotation state of the front color wheel and the rear color wheel between a first rotation state and a second rotation state;
The front color wheel and the rear color wheel are alternately provided with a color filter that transmits only light belonging to a predetermined wavelength range and a white filter that transmits all visible light regardless of the wavelength range along the rotation direction. ,
In the first rotation state, both of the two color wheels rotate while maintaining a positional relationship in which light transmitted through the white filter of the preceding color wheel enters the color filter of the subsequent color wheel,
In the second rotation state, an illumination device in which only the front color wheel rotates while maintaining a positional relationship in which light transmitted through the color filter and white filter of the front color wheel enters the white filter of the rear color wheel. The front color wheel is provided with a red filter that transmits only light that belongs to the red wavelength range and a green filter that transmits only light that belongs to the green wavelength range with a first white filter interposed therebetween, and the green filter And a blue filter that transmits only light belonging to the blue wavelength region is provided with a second white filter interposed therebetween, and the blue filter and the red filter are provided with a third white filter interposed therebetween,
The latter color wheel is provided with a red filter that transmits only light belonging to the red wavelength region and a green filter that transmits only light belonging to the green wavelength region with a fourth white filter interposed therebetween, and the green color A filter and a blue filter that transmits only light in the blue wavelength range are provided with a fifth white filter interposed therebetween, and the blue filter and the red filter are provided with a sixth white filter interposed therebetween,
In the first rotation state, the light transmitted through the first white filter of the front color wheel is incident on the red filter of the rear color wheel, and the light transmitted through the second white filter of the front color wheel is the Both the two color wheels rotate while maintaining the positional relationship where the light incident on the green filter of the rear color wheel and transmitted through the third white filter of the front color wheel enters the blue filter of the rear color wheel. The lighting device according to claim 1. A light source;
A pre-stage color wheel on which light emitted from the light source is incident;
A rear color wheel on which light transmitted through the front color wheel is incident;
Control means for switching the rotation state of the front color wheel and the rear color wheel between a first rotation state and a second rotation state;
The preceding stage color wheel includes a red filter that transmits only light belonging to the red wavelength range, a green filter that transmits only light belonging to the green wavelength range, and a blue filter that transmits only light belonging to the blue wavelength range. And a white filter that transmits all visible light regardless of the wavelength range, is provided along the rotation direction,
The latter color wheel is provided with a color filter having a transmission wavelength range different from the red filter, the green filter and the blue filter, and a white filter which transmits all visible light regardless of the wavelength range, along the rotation direction.
In the first rotation state, the two color wheels are maintained while maintaining a positional relationship in which light transmitted through a part of the white filter provided in the preceding color wheel is incident on the color filter provided in the subsequent color wheel. Both rotate,
In the second rotation state, only the front color wheel is maintained while maintaining the positional relationship in which the light transmitted through the color filter and the white filter provided in the front color wheel is incident on the white filter provided in the rear color wheel. Rotating device.   The white filter of the preceding color wheel is provided between the green filter and the blue filter of the preceding color wheel, and is adjacent to the green filter among the white filters of the preceding color wheel in the first rotation state. The lighting device according to claim 3, wherein a positional relationship in which a part of the light is incident on the yellow filter of the subsequent color wheel is maintained. A positioning light source, a wavelength selection filter on which light emitted from the positioning light source and transmitted through the front and rear color wheels and a subsequent color wheel are incident, and a light receiving element that receives the light transmitted through the wavelength selection filter Having a detection means
The lighting device according to claim 1, wherein the control unit controls a positional relationship between the front color wheel and the rear color wheel based on a detection result of the detection unit.   The illumination device according to claim 5, wherein the alignment light source is a white light source, and the wavelength selection filter has a characteristic of blocking light belonging to a blue wavelength region.   The illumination device according to claim 5, wherein the alignment light source is a white light source, and the wavelength selection filter has a characteristic of transmitting only light belonging to a blue wavelength region.   A projection display device that modulates light emitted from an illumination device by a light valve to form image light, and projects the formed image light through a projection lens, wherein the illumination device comprises claims 1 to Item 8. A projection display device which is the illumination device according to any one of Items 7 to 8.

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