JP2008181032A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector of a DLP (Digital Light Processing) system in which two color wheels are efficiently arranged so as to be usable both for a cinema mode and a presentation mode. <P>SOLUTION: The projector 1 is equipped with an optical engine 5 including an integrator 15, a first color wheel 11 placed in the entrance side of the integrator 15, and a second color wheel 12 placed in the exit side of the integrator 15, wherein the first and second color wheels 11, 12 are placed to produce the same beam spot diameters on the first and second color wheels 11, 12. The projector includes: a presentation mode in which the both color wheels 11, 12 are rotated to allow color filters in the same colors to overlap each other on the optical path; and a cinema mode in which the both color wheels are rotated to allow color filters of red, green and blue of one wheel to overlap a colorless transparent color filter of the other wheel on the optical path. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a DLP (Digital Light Processing) (registered trademark) projector.

  2. Description of the Related Art Conventionally, there has been known a projector that forms an image by an image generating element using light emitted from a lamp based on image data from a personal computer or a video camera, and projects the image on a screen or the like.

  As one type of projector of this type, a large number of mirror elements are regularly arranged vertically and horizontally, and an image is projected on a screen using a DMD (Digital Mirror Device) (registered trademark) that can individually control each mirror element. There is a DLP method.

  In this DLP projector, each mirror element of the DMD is driven individually in one of two directions, a direction in which illumination light is incident on a projection lens or a direction in which it is not incident, based on an image projected on a screen. As a result, the image is projected on the screen.

  An image by illumination light incident on the projection lens is projected on the screen. As is well known, in the DLP projector, the total number of mirror elements in the DMD is the number of pixels of the image projected on the screen. DMD mirror elements are very small. For example, in an area of 20 mm × 35 mm, 2.3 million elements can be arranged. Therefore, by using a DMD having a larger total number of mirror elements, an increase in size of the optical system can be suppressed, and a high-definition image having a larger number of pixels can be projected on the screen.

  In a DLP projector, a plurality of optical components such as a color wheel, an integrator, a lens, a mirror, and a DMD are arranged in an optical path from a light source to a projection lens. Various types of optical components and their arrangements have been proposed depending on the purpose, and one of them is the type and arrangement of color wheels.

  The color wheel has a substantially disk shape in which red (R), green (G), blue (B), and colorless and transparent (W) color filters are arranged in the direction of rotation. It rotates as a heart and time-divides the transmitted light. In the DLP projector, the luminance and color reproducibility of the projected image are determined by the arrangement of the color filter of the color wheel, so that a color wheel suitable for the application is mounted.

  For example, a color wheel for cinema (video viewing) used for watching movies, a color for presentation (description screen display) used for explanation while displaying spreadsheets, graphs, documents, etc. on a personal computer There is a wheel. Cinema color wheels are usually arranged with RGB color filters occupying about one third of the color area on the color wheel, so that color reproducibility is achieved by using only primary color filters. Excellent. However, since each primary color is used only for a part of the image display period, there is a drawback that the brightness of the entire image is lowered.

  On the other hand, a color wheel for presentation is usually provided with RGBW color filters, and there is a period during which a color image is projected as a monochrome image by the W color filter. Thereby, the brightness when a bright image is input can be improved. However, there is a drawback that the colored portion becomes darker and the color reproducibility becomes worse as an image.

  Thus, it is difficult to satisfy both color reproducibility and luminance with one color wheel, and there is a problem in using one projector for general purposes. Various techniques have been proposed to solve this problem.

For example, Patent Document 1 discloses a projector that provides a plurality of color wheels on an optical path and controls the combination of color filters. Further, Patent Document 2 discloses a projector that includes a plurality of color wheels and uses any one of the color wheels by moving it on the optical path. In Patent Document 3, the color wheel filter is configured such that the color sequence arranged in the rotation direction is different at least between the outer peripheral portion and the inner peripheral portion, and the white light emitted from the light source is condensed on the color wheel. There has been disclosed a projector in which the position is variable.
JP 2006-162658 A JP 2004-294985 A JP 2004-317528 A

  However, Patent Documents 1 to 3 do not particularly limit the positional relationship of the color wheel. For example, when two color wheels are arranged, two motors are required to drive them, and it is necessary to devise efficient arrangement of a bulky motor in a limited space.

  In addition, when the color wheels are arranged in an overlapping manner, it is necessary to arrange them with an interval in consideration of rotation blur of the color wheel, and therefore the light spot diameters on the respective color wheels are different. Normally, when an image is output while the light spot passes through the boundary area (black box point) of each color of the color filter, the image is not output because it is mixed. Therefore, if the light spot diameters are different, the larger light spot diameter must be used as the black box point, and the image output time for one turn of the color wheel is shortened, so that the light utilization rate is reduced and the brightness of the projected image is reduced. Decreases.

  An object of the present invention is to provide a DLP projector in which two color wheels are efficiently arranged so that they can be used for both cinema and presentation.

  In order to achieve the above object, the present invention provides a projector including an optical engine having a lamp and an integrator that emits incident light as planar light, and includes a first color on an optical path on the incident side of the integrator. The wheel is characterized in that a second color wheel is provided on the light path on the emission side.

  In the projector described above, it is desirable that the first and second color wheels are arranged coaxially from the viewpoint of facilitating the rotation control of the color wheel.

  In the projector described above, it is preferable that the first and second color wheels are driven by first and second motors, respectively, and both motors are disposed on the integrator side of the color wheel.

  According to this configuration, the first and second motors are arranged in a space surrounded by the integrator and the first and second color wheels, which cannot be made smaller. A bulky motor can be efficiently arranged in a limited space of the optical engine. Therefore, since it is not necessary to change the arrangement of other members to provide a space in order to arrange the motor, it is possible to suppress an increase in the size of the projector.

  In the projector described above, it is preferable that the first and second color wheels are arranged so that the light spot diameters on the first and second color wheels are the same. If each light spot diameter is different, the black box point must be provided for the larger diameter, the image output time for one turn of the color wheel is shortened, the light utilization rate is reduced, and the brightness of the projected image is reduced. This is because of a decrease.

  In the projector described above, the first and second color wheels have red, green, blue, and colorless and transparent color filters, and the two color wheels are rotated so that the color filters of the same color overlap each other on the optical path. By providing the presentation mode to be performed, it is possible to improve the luminance when a bright image is input.

  In the projector described above, the first and second color wheels have red, green, blue, and colorless and transparent color filters, and the red, green, and blue color filters are colorless in the optical path. By providing a cinema mode that rotates so as to overlap the transparent color filter, only the primary colors of red, green, and blue are projected, so that an image with excellent color reproducibility can be projected.

  In the projector described above, the optical engine further includes at least one lens that expands light emitted from the second color wheel, a mirror that reflects light emitted from the lens, and light reflected from the mirror. It is desirable to include an enlarging relay lens, an image generation element that modulates light emitted from the relay lens into image light, and a projection lens that projects image light from the image generation element.

  Preferably, the image generating element is a digital mirror device in which a plurality of mirror elements are regularly arranged in the vertical and horizontal directions and each mirror element can be individually controlled.

  When the present invention is embodied, a first color wheel having a lamp, a color filter of red, green, blue, and colorless and transparent, time-dividing light emitted from the lamp, and from the first color wheel, A rod-type integrator that emits the emitted light as planar light and a color filter of red, green, blue, and colorless and transparent, are arranged coaxially with the first color wheel, and are output from the integrator. A second color wheel for time-sharing the light; and first and second motors disposed on the integrator side of the first and second color wheels and driving the first and second color wheels, respectively A doublet lens that expands the light emitted from the second color wheel, a mirror that reflects the light emitted from the doublet lens, and a relay lens that expands the light reflected from the mirror A plurality of mirror elements regularly arranged vertically and horizontally, each mirror element can be individually controlled, and a digital mirror device that modulates light emitted from the relay lens into image light, and image light from the digital mirror device A projector having an optical engine having a projection lens for projecting the first and second color wheels, wherein the first and second color wheels are arranged such that the light spot diameters on the first and second color wheels are the same. , Both the color wheels are rotated so that the color filters of the same color overlap each other on the optical path, and both color wheels are the color filters of the red, green, and blue color filters that are colorless and transparent on the optical path. It is configured to have a cinema mode that rotates so as to overlap.

  According to the present invention, by providing the first color wheel on the optical path on the incident side of the integrator and the second color wheel on the optical path on the output side, it can be used for both cinema and presentation. A DLP projector in which two color wheels are efficiently arranged can be provided.

  Further, by arranging the first and second motors for driving the first and second color wheels on the integrator side of both color wheels, a space surrounded by the integrator and the first and second color wheels is obtained. In this case, the first and second motors are arranged in a space that cannot be made smaller, and therefore a bulky motor can be efficiently arranged in a limited space of the optical engine. Therefore, since it is not necessary to change the arrangement of other members to provide a space in order to arrange the motor, it is possible to suppress an increase in the size of the projector.

  Furthermore, by arranging the first and second color wheels so that the light spot diameters on the first and second color wheels are the same, the light utilization rate is improved and the brightness of the projected image is improved. Can do.

  FIG. 1 is a perspective view showing the appearance of the projector, and FIG. 2 is a partially cutaway plan view showing the configuration of the optical engine of the projector shown in FIG. The projector 1 is an apparatus that forms an image by an image generation element 3 using light emitted from a lamp 2 based on image data from a personal computer, a video camera, or the like, and projects the image onto a screen or the like through a projection lens 4. It is. In FIG. 2, the alternate long and short dash line indicates the optical axis.

  The projector 1 includes an optical engine 5 including a lamp 2 and an image projection optical system 10 including an image generation element 3 and a projection lens 4. The optical engine 5 is covered with a housing 20.

  The lamp 2 has an ellipsoidal reflector and a light source that emits light for image projection at a first focal point thereof. As the reflector, a parabolic mirror, an elliptical mirror, or the like can be used. For example, a light source that emits white light is used as the light source, and a halogen lamp, a metal halide lamp, a high-pressure mercury lamp, or the like can be used.

  The image projection optical system 10 forms an image using light from the lamp 2 and projects the image. In addition to the image generation element 3 and the projection lens 4, the first and second color wheels are provided. 11, 12, first and second motors 13, 14, integrator 15, doublet lens 16, mirror 17, relay lens 18, and circuit board 19.

  The image generating element 3 is an element that forms an image by reflecting light, and thereby modulates incident light into image light. The image generating element 3 is provided on the circuit board 19. As the image generating element 3, it is desirable to use a DMD in which a large number of mirror elements are regularly arranged vertically and horizontally and each mirror element can be controlled individually.

  The projection lens 4 is a lens group that projects light reflected by the image generation element 3, that is, image light from the image generation element 3, and is disposed at a position facing an opening 21 provided in the housing 20. By using the lens group, the unclearness of the projected image due to the chromatic aberration of each color light is prevented.

  The first color wheel 11 is provided on the light path on the incident side of the integrator 15 and has a substantially disk shape in which R, G, B, and W color filters are arranged in the rotation direction. The motor 13 rotates about the rotation shaft 11a as an axis, and the light emitted from the lamp 2 is separated into R, G, B, and W light in a time division manner.

  The second color wheel 12 is provided coaxially with the first color wheel on the optical path on the emission side of the integrator 15, and is formed by arranging R, G, B, and W color filters in the rotation direction. It has a disk shape, and is rotated about the rotation shaft 12a by the second motor 14, and the light emitted from the integrator 15 is separated into R, G, B, and W light in a time-sharing manner.

  The 1st motor 13 is being fixed to the rotating shaft 11a of the 1st color wheel 11, and rotates the 1st color wheel 11 by the drive. The first motor 13 is disposed on the integrator 15 side of the first color wheel 11.

  The 2nd motor 14 is being fixed to the rotating shaft 12a of the 2nd color wheel 12, and rotates the 2nd color wheel 12 by the drive. The second motor 14 is disposed on the integrator 15 side of the second color wheel 12.

  As described above, by arranging the first and second motors 13 and 14 on the side of the integrator 15, a space surrounded by the integrator 15 and the first and second color wheels 11 and 12, Since the first and second motors 13 and 14 are disposed in the space that cannot be reduced, the bulky motors 13 and 14 are efficiently disposed in the limited space of the optical engine 5. Can do. Therefore, since it is not necessary to change the arrangement of other members to provide a space in order to arrange the motors 13 and 14, the size of the projector 1 can be suppressed.

  The integrator 15 makes the incident light uniform and emits it as planar light, and the incident surface is arranged near the second focal point of the lamp 2. The integrator 15 is preferably a rod type that emits the light emitted from the first color wheel 11 as planar light. As the rod, a solid rod such as a glass rod or a hollow rod having an inner surface as a mirror surface can be adopted. According to the solid type rod, the reflectance in the inner surface reflection inside the rod can be almost 100%, so that the light efficiency is better than that of the hollow type.

  The doublet lens 16 is composed of two lenses that expand the light emitted from the second color wheel 12. In place of the doublet lens 16, one lens or three or more lens groups may be used. The mirror 17 reflects the light emitted from the doublet lens 16, and makes the image projection optical system 10 compact by bending the optical path. The relay lens 18 is a lens that enlarges reflected light from the mirror 17.

  Here, since the planar light emitted from the integrator 15 is enlarged to cover the image generating element 3 using the doublet lens 16 and the relay lens 18, one of the lenses is eliminated and only the other lens is used. You may make it play the role.

  Further, in the configuration of the optical engine 5 described above, the first and second color wheels 11 and 12 are slightly shaken at the time of rotation. Therefore, the first and second color wheels 11 and 12 need to be separated from the integrator 15 as much as possible. It is desirable to arrange it close to 15. The reason will be described below.

  FIG. 3 is a diagram for explaining the arrangement of the color wheels 11 and 12. FIG. 3 shows a state in which the first and second color wheels 11 and 12 are arranged as close to the integrator 15 as possible. The two-dot chain line indicates the outermost optical path. As shown in FIG. 3, the lamp 2 and the integrator 15 are arranged so that the light emitted from the lamp 2 converges on the incident surface 15 a of the integrator 15. Since the first color wheel 11 is arranged at a predetermined distance from the integrator 15, the emitted light from the lamp 2 becomes a light spot S 1 having a predetermined diameter d 1 on the first color wheel 11. If the first color wheel 11 is further arranged at the position A further away from the integrator 15, the diameter d2 of the light spot S2 at that position becomes larger than d1.

  FIG. 4 is a plan view of the color wheel 11. The color filters are arranged so that the R, G, and B segments are each 60 °, and the W segment is 180 °. As shown in FIG. 4, while the light spot passes through the boundary area (black box point) of each color of the color filter, since the color is mixed when the image is output, the image is not output. Therefore, if the diameter increases like the light spot S2, the diameter must be set as a black box point, and the image output time for one turn of the color wheel 11 is shortened. Thereby, the light utilization rate at the time of the light spot S2 is lower than that at the time of the light spot S1, and the luminance of the projected image is reduced. That is, it can be said that the smaller the light spot diameter on the color wheel, the better.

  In order to reduce the light spot diameter on the first color wheel 11, the first color wheel 11 may be disposed as close to the incident surface 15 a of the integrator 15 as possible. In addition, since the emitted light from the emitting surface 15b of the integrator 15 gradually diverges, similarly, the second color wheel 12 may be disposed as close to the emitting surface 15b of the integrator 15 as possible.

  Furthermore, it is desirable that the first and second color wheels 11 and 12 are arranged so that the light spot diameters on the first and second color wheels 11 and 12 are the same. Even if the first and second color wheels 11 and 12 are arranged as close to the integrator 15 as possible, if the diameters of the respective light spots are different, the black box points must be provided for the larger diameter. It is. The risk of collision between the color wheel and the integrator 15 can be reduced by separating one of the color wheels from the integrator 15 as much as possible.

  Next, operation control of the first and second color wheels 11 and 12 will be described. At the time of image output, the first and second color wheels 11 and 12 rotate at the same speed and are controlled so that the positional relationship between the color filters of the first and second color wheels 11 and 12 is constant. Then, the projector 1 has a presentation mode in which the two color wheels 11 and 12 are rotated so that the same color filters overlap each other on the optical path, and both the color wheels 11 and 12 are R, G, and R on the optical path. And a cinema mode in which the B color filter is rotated so as to overlap the W color filter. These modes are switched by a mode switch (not shown).

  The presentation mode is a mode in which the brightness when a bright image is input is improved, and is suitable for explanation while displaying spreadsheets, graphs, documents, etc. on a personal computer. On the other hand, the cinema mode is a mode with excellent color reproducibility, and is suitable for movie viewing and television viewing.

  First, the presentation mode will be described. FIG. 5A is a diagram illustrating a state of the first color wheel 11 at a certain time in the presentation mode, and FIG. 5B is a diagram illustrating the state of the second color wheel at the time illustrated in FIG. FIG. 5C illustrates a state in which the first color wheel 11 in the state of FIG. 5A and the second color wheel 12 in the state of FIG. 5B are overlapped on the optical path. FIG.

  As shown in FIGS. 5A and 5B, the first and second color wheels 11 and 12 are rotated in synchronization so that the same color segments of RGBW overlap each other. Thereby, from the viewpoint of light transmission, the same transmitted light as in the case of using one color wheel made of RGBW as shown in FIG. 5C can be obtained. Image output may be performed corresponding to four segments. Therefore, since white light that has passed through W after RGB is projected, it is possible to improve luminance when a bright image is input.

  In addition to the above, the color wheel is controlled in the presentation mode by stopping one color wheel 11 or 12 at a position where W transmitted light is obtained and rotating the other color wheel 11 or 12 as usual. However, the same effect can be obtained.

  Next, the cinema mode will be described. FIG. 6A is a diagram illustrating a state of the first color wheel 11 at a certain point in the cinema mode, and FIG. 6B is a diagram illustrating the state of the second color wheel at the point of FIG. FIG. 6C illustrates a state in which the first color wheel 11 in the state of FIG. 6A and the second color wheel 12 in the state of FIG. 6B are overlapped on the optical path. FIG.

  As shown in FIGS. 6A and 6B, the first and second color wheels 11 and 12 are rotated in a state where the relative positional relationship between the color filters is shifted by 180 °. Thus, from the viewpoint of light transmission, one R, G, B color filter overlaps the other W color filter as shown in FIG. The same transmitted light can be obtained as when using the color wheel. Image output may be performed corresponding to 6 segments. Therefore, since only RGB primary colors are projected, an image with excellent color reproducibility can be projected.

  The first and second color wheels used in the present invention are not limited to the four-segment type shown in FIG. 4, but also the eight-segment type of R, G, B, and W, and the first and second color wheels. Wheels with different segment configurations can also be used. That is, the first and second color wheels are not particularly limited in the configuration of the segments, and by changing the overlapping manner, a pattern that can obtain the R, G, B, and W transmitted light necessary for the presentation mode is obtained. It is only necessary to realize a pattern capable of obtaining R, G, B transmitted light necessary for the cinema mode.

  The present invention can be used for a DLP projector.

1 is a perspective view showing an external appearance of a projector according to the present invention. It is the partially broken top view which shows the structure of the optical engine of the projector of FIG. It is a figure explaining arrangement | positioning of a color wheel. It is a top view of a color wheel. (A) is a diagram showing the state of the first color wheel at a certain point in the presentation mode, (b) is a diagram showing the state of the second color wheel at the point of FIG. 5 (a), (c) is FIG. 6 is a view of the first color wheel in the state of FIG. 5A and the second color wheel in the state of FIG. (A) is a figure which shows the state of the 1st color wheel in a certain time in cinema mode, (b) is a figure which shows the state of the 2nd color wheel in the time of FIG. 6 (a), FIG. 6C is a view of the first color wheel in the state of FIG. 6A and the second color wheel in the state of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2 Lamp 3 Image generation element 4 Projection lens 5 Optical engine 11 1st color wheel 12 2nd color wheel 13 1st motor 14 2nd motor 15 Integrator 16 Doublet lens 17 Mirror 18 Relay lens

Claims (9)

A lamp,
A first color wheel having a color filter of red, green, blue, colorless and transparent, and time-dividing light emitted from the lamp;
A rod-type integrator that emits light emitted from the first color wheel as planar light; and
A second color wheel having a color filter of red, green, blue, colorless and transparent, arranged on the same axis as the first color wheel, and time-dividing light emitted from the integrator;
First and second motors disposed on the integrator side of the first and second color wheels, respectively, for driving the first and second color wheels;
A doublet lens for enlarging light emitted from the second color wheel;
A mirror that reflects light emitted from the doublet lens;
A relay lens that expands the reflected light from the mirror;
A plurality of mirror elements are regularly arranged vertically and horizontally, each mirror element can be individually controlled, and a digital mirror device that modulates light emitted from the relay lens into image light,
A projector comprising an optical engine having a projection lens for projecting image light from the digital mirror device,
Arranging the first and second color wheels such that the light spot diameters on the first and second color wheels are the same;
The presentation mode in which the two color wheels are rotated so that the color filters of the same color overlap each other on the optical path, and the red, green, and blue color filters overlap the colorless and transparent color filter in the optical path. And a cinema mode for rotating the projector. In a projector including an optical engine having a lamp and an integrator that emits incident light as planar light,
A projector comprising a first color wheel on an optical path on an incident side of the integrator and a second color wheel on an optical path on an output side.   The projector according to claim 2, wherein the first and second color wheels are arranged coaxially.   4. The projector according to claim 2, wherein the first and second color wheels are driven by first and second motors, respectively, and both motors are disposed on the integrator side of the color wheel. 5.   The projector according to any one of claims 2 to 4, wherein the first and second color wheels are arranged so that light spot diameters on the first and second color wheels are the same. The first and second color wheels have red, green, blue, colorless and transparent color filters,
6. The projector according to claim 2, further comprising a presentation mode in which both color wheels are rotated so that color filters of the same color overlap each other on the optical path. The first and second color wheels have red, green, blue, colorless and transparent color filters,
7. The cinema mode according to claim 2, further comprising: a cinema mode in which the two color wheels are rotated such that the red, green, and blue color filters overlap the colorless and transparent color filter on the optical path. projector. The optical engine further includes:
One or more lenses for magnifying light emitted from the second color wheel;
A mirror that reflects the light emitted from the lens;
A relay lens that expands the reflected light from the mirror;
An image generating element that modulates light emitted from the relay lens into image light;
The projector according to claim 2, further comprising a projection lens that projects image light from the image generation element.   9. The projector according to claim 8, wherein the image generation element is a digital mirror device in which a plurality of mirror elements are regularly arranged in the vertical and horizontal directions, and each mirror element can be individually controlled.

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