JP2006139101A - Image display device and optical unit thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection apparatus and an optical unit thereof capable of improving the quality of a display image by matching the scanning amounts of each color light accompanying movement on a panel (video display element).
SOLUTION: Light emitted from a light source 1 is separated into R, G, and B color light, is incident on different regions on a video display element 12 by a polygon mirror 13, and is converted into a video signal by light emitted from each region. In the optical unit of the projection apparatus that forms a corresponding optical image and enlarges / projects it onto the screen via the projection lens 23, an optical path for guiding each color light separated into R, G, and B onto the reflection surface of the polygon mirror 13 Are configured so as to be incident substantially perpendicular to the reflecting surface, so that the scanning amounts of the respective color lights accompanying the movement on the image display element are matched.
[Selection] Figure 1

Description

  The present invention uses a so-called light valve element such as a liquid crystal panel or an image display element to project an image on a screen, for example, a liquid crystal projector apparatus, a reflective image display projector apparatus, a projection In particular, it relates to an optical unit such as a rear projection television, and a projection-type image display device. In addition, the present invention relates to an image display apparatus that obtains and projects a color image by sequentially moving the irradiation area, and further relates to an optical unit therefor.

Conventionally, after passing light from a lamp through, for example, first and second array lenses, a polarizing beam splitter (PBS), and a collimator lens, R light, B light, and G light are used using a plurality of dichroic mirrors. Each of the separated light beams is changed by using a rotating reflective polyhedron so that each light beam is different on one light valve element (hereinafter simply referred to as “panel”). A projection apparatus and an optical unit for the projection apparatus that irradiate an area where each light is irradiated and sequentially move (scroll) the light irradiation area on the panel in a certain direction are already disclosed in, for example, the following patent documents: Are known.
JP 2002-328332 A JP 2003-255250 A

  In the projection apparatus and the optical unit according to the above-described prior art, by using one rotating reflective polyhedron, each separated light is irradiated to different positions on the panel, thereby mixing a plurality of light colors and This realizes a projection device with improved contrast utilization and improved light utilization efficiency and an optical unit therefor. However, due to the configuration of the optical system including the rotating reflective polyhedron, the scan amount of each color light accompanying the movement (scrolling) on the panel does not match, so the brightness of the projected image is There is still a problem in the quality of the projected image displayed, such as the difference in color or the change in color.

  Therefore, in the present invention, in view of the above-described problems in the prior art, in particular, by using a reflective reflective polyhedron to irradiate each separated light on a different area on the panel, a plurality of light beams are emitted. In a projection device with improved color mixing and contrast degradation and good light use efficiency, or an optical unit therefor, it is possible to match the scan amount of each color light accompanying movement on the panel (video display element). Therefore, an object of the present invention is to provide a projection apparatus capable of improving the quality of a display image, and an optical unit therefor.

  According to the present invention, in order to achieve the above-described object, first, a light source, color separation means for separating the light emitted from the light source into a plurality of color lights, and each color light emitted from the color separation means A video display element that is incident on different areas and forms an optical image according to a video signal by emission from each area, and a plurality of color lights emitted from the color separation means, changing the direction of each optical axis thereof, A rotating polyhedron that irradiates different areas of the image display element while moving the areas irradiated with the plurality of color lights in a predetermined direction, and a projection device that projects light emitted from the image display element as an image. The optical unit further includes an optical path for guiding a plurality of color lights from the color separation means to the rotating polyhedron, wherein the optical paths of the plurality of color lights are applied at a predetermined angle. The optical unit of the image display device is configured so as to enter or input-output substantially perpendicular to the single plane which constitutes the rotating polygon is provided.

  According to the present invention, in the optical unit described above, the rotating polyhedron is preferably a reflective rotating polyhedron having a surface as a reflecting surface, and moreover, the plurality of color lights from the color separation means The optical path for guiding to the rotating polyhedron is further configured such that each color light emitted from the color separation means is incident on the reflecting surface of the reflective rotating polyhedron with a substantially equal optical length, Alternatively, the optical path for guiding the plurality of color lights from the color separation means to the rotating polyhedron is such that each color light emitted from the reflecting surface of the reflective rotating polyhedron scans the image display element uniformly. It is preferable to be configured.

Furthermore, in the present invention, in the optical unit described above, an optical path for guiding a plurality of color lights from the color separation unit to the rotating polyhedron is a light path of at least three colors emitted from the color separation unit. It is preferable that irradiation is performed on the reflective surface of the reflective rotary polyhedron so as to satisfy the above condition.
θ1: −a + α ≦ θ1 ≦ + a + α
θ2: −a ≦ θ2 ≦ + a
θ3: −a−α ≦ θ3 ≦ + a−α
However, (theta) 1- (theta) 3 represents the area | region of the rotation angle of the said rotation polyhedron corresponding to each color light, and (alpha) is with respect to the deflection angle of center color light among the light of three colors irradiated on the said reflective surface. The amount of deviation of the rotation angle of the rotating polyhedron of other color light is shown.

  According to the present invention, in the optical unit described above, the plurality of color lights in the vicinity of the reflection surface of the reflective rotary polyhedron is arranged on an optical path for guiding a plurality of color lights from the color separation unit to the rotary polyhedron. It is preferable to include an optical system that forms a light source image.

  In addition, according to the present invention, together with the optical unit described above, a power supply unit for supplying predetermined power to the light source in the optical unit, and a video signal to the video display element in the optical unit There is provided a video display device in which a video signal processing unit for storing the video signal processing unit is housed in a housing.

  As described above, according to the optical unit and the video display device using the optical unit according to the present invention, each separated light is transmitted to different regions on the video display element using a rotating polyhedron. In the optical unit of the image display device that forms a color image by irradiation and projects the formed color image by the projection means, the scan amount of each color light accompanying the movement (scan or scroll) on the image display element Therefore, the quality of the display image can be improved.

Several embodiments according to the present invention will be described below with reference to the accompanying drawings.
First, FIG. 1 is a block diagram showing an outline of an image display apparatus according to a first embodiment of the present invention, in particular, an optical unit as a main component. In this figure, reference numeral 1 denotes a lamp that is a light source. In particular, in recent years, for example, in an optical unit in a projection apparatus such as a liquid crystal projector apparatus, a reflective video display projector apparatus, or a projection type rear projection television, In order to ensure the brightness of the projected image, for example, a high-power lamp such as a xenon lamp, a metahalide lamp, or an ultrahigh pressure mercury lamp is used. However, the present invention is not limited to this, and in the present invention, a light source such as an LED or an electrodeless lamp can be used instead of the above lamp. Reference numeral 2 in the figure denotes a reflector attached around the lamp 1, which is the light source, and the reflector 2 has an internal mirror surface formed, for example, in a hyperbola shape so that the lamp (arc) 1 is formed. The light emitted from is reflected and collected (see the broken line in the figure), and the resulting light is irradiated onto the incident window of the polarization conversion element 4. The polarization conversion element 4 converts random polarized light into S-polarized light or P-polarized light by a combination of a polarization beam splitter and a 1 / 2λ wavelength plate.

  As described above, the light from the light source 1 collected through the reflector 2 is aligned with the polarization direction of either S-polarized light or P-polarized light through the polarization conversion element 4 and then the light. A plurality of lenses (in this example, three convex lenses 6) are reflected and transmitted through the pipe 3 (or also called an integrator or a light funnel, and made of a glass pipe) at a predetermined emission angle (F value). 7 and 8). Further, the light emitted from the plurality of primary imaging lens groups 6, 7, and 8 is, for example, tilted and attached to a plurality (three in this example) of reflection mirrors (dichroic mirrors) 9R, 9G, and 9B. The light is incident on a color separation element 9 that separates white light into a plurality of color lights, and is separated into R, G, and B colors. The color separation element 9 includes, for example, an R dichroic mirror 9R that reflects R light, a G dichroic mirror 9G that reflects G light, and a B dichroic mirror 9B that reflects B light. The light is reflected as R light, G light, and B light, respectively. The R dichroic mirror 9R that reflects the R light transmits the G light and the B light. The G dichroic mirror 9G that reflects the G light transmits the B light. In this way, R light, G light, and B light are separated and reflected by the color separation element 9. The color separation element 9 can be constituted by a plurality of color filters such as R, G, B, W (white) color light, and a color prism, for example, instead of the reflection mirror described above.

  The light separated into the three colors R, G, and B as described above is, for example, in the illustrated example, a secondary imaging lens group 25 constituted by three convex lenses, a polarizing beam splitter (hereinafter referred to as “PBS (Polarized)”. Beam splitter) ”, 10, and further, through a ¼λ wave plate 5 b, a reflection type rotating polyhedron, so-called polygon mirror 13, is irradiated at a different location on the reflection surface and reflected by the reflection surface. The At this time, the light separated into the three colors R, G, and B is divided into a plurality by the secondary imaging lens group 25 in the vicinity of the reflecting surface of the polygon mirror 13 (before and after the reflecting surface, about several mm). The secondary light source image is formed. Thereafter, the optical axis of each color light is configured to be incident substantially perpendicularly when the polygon mirror 13 is at a predetermined angle, and is reflected by one surface of the polygon mirror 13 and then substantially perpendicular to the incident optical axis. The light is emitted in the direction. At this time, the predetermined angle is a rotation angle at a position where the center line passing through the center of one surface of the polygon mirror 13 and the rotation center of the polygon mirror 13 is horizontal to the incident optical axis. In the figure, the polygon mirror 13 which is the reflection type rotating polyhedron is shown as an example composed of eight reflecting surfaces composed of curved surfaces having an aspherical shape. However, the number of the reflecting surfaces is as follows. It is not limited, and the reflective surface may be formed in a reverse curved surface or a flat surface. In this case, the aspherical shape may be a shape for keeping the moving speed of light on the panel constant. Specifically, the curvature of the end portion from the center of the shape of one surface of the polygon mirror 13 is gradually changed. Thus, simultaneously with the rotation of the polygon mirror 13, it is possible to make the amount of change in the reflection angle close to a constant value when the angle of the reflected light changes. In addition, when R light, G light, and B light are reflected on one reflective surface of this polygon mirror 13, the optical axes of each light are once crossed. Further, when any two lights of R light, G light, and B light are reflected by one surface of the polygon mirror 13, the optical axes of these lights intersect. The crossing position may be the position of the stop of the tertiary imaging system to the panel.

  The light reflected by the reflection surface of the polygon mirror 13 is transmitted again through the ¼λ wavelength plate 5b and the PBS 10, and further, convex lens groups 14, 15, 16 constituting the tertiary imaging lens group, and , Is incident on the PBS 18 formed by forming a dielectric band multilayer type PBS or a multilayer film type PBS at the interface of the two prisms via the 1 / 2λ wavelength plate 5a, and reflected at the interface ( S-polarized light), a quarter-wave plate for aligning the polarization direction of the incident light, or a contrast adjustment element (for example, made of a convention film or a trim retarder) 5c on a panel that is a single-plate reflective image display element 12 Different places (regions) are irradiated. The polarizing beam splitter (PBS) 18 may be a flat plate PBS made of a wire grid or the like, or a PBS having a configuration in which the wire grid is sandwiched between glass prisms. The single-plate reflective image display element 12 can be constituted by, for example, a reflective liquid crystal panel called LCOS or a reflective micromirror device type panel. Thereafter, the light (P-polarized light) reflected by the single-plate reflective image display element 12 is again transmitted to the projection lens 23 via the ¼λ wavelength plate 5c and the PBS 18, and further through the polarizing plate 17b. Incident light is projected on the screen (not shown) through the projection lens 23 in an enlarged manner.

  That is, according to the optical unit of the video display device according to the present invention, the detailed configuration of which has been described above, the randomly polarized light from the light source 1 is converted into predetermined polarized light by the polarization conversion element 4 and the light valve 3. (In this example, it is polarized to S-polarized light) and guided to the color separation element 9 through a primary imaging system composed of a plurality of lenses 6, 7, 8, where R, G, B Are separated into three colors of light. Thereafter, the separated light is irradiated onto the reflecting surface of the rotating polygon mirror 13 through a secondary imaging system including a plurality of lenses 25, a PBS 10, and a quarter-wave plate 5b. Light of three colors R, G, and B is moved at a constant speed in a predetermined direction. Then, in addition to the 1 / 4λ wavelength plate 5b and the PBS 10, a plurality of lens groups 14, 15, 16 and a tertiary imaging system including a 1 / 2λ wavelength plate 5a, a PBS 18, and a 1 / 4λ wavelength plate 5c are used. Thus, light of the three colors R, G, and B moving at a constant speed in a predetermined direction is irradiated onto different areas on the single-plate reflective video display element 12. Thereafter, the three colors of light reflected on the single-plate reflective image display element 12 are transmitted through the quarter-wave plate 5c, PBS 18, and polarizing plate 17b, enter the projection lens 23, and are enlarged and projected. The image formed on the single-plate reflection-type image display element 12 is enlarged and projected and displayed on the screen.

  In the image display device according to the present invention, in particular, in the optical unit thereof, the R, G separated by the color separation element 9 as an optical path to the reflection surface of the polygon mirror 13 as is apparent from FIG. , B light passes through the secondary imaging lens group 25 and then is reflected by the PBS 10 so that the polygon mirror 13 which is the reflective rotary polyhedron has a predetermined angle (in this case, 0 °). At the position, the light enters and exits substantially perpendicular to the reflecting surface of the polygon mirror 13. In other words, as shown in the left figure of the attached FIG. 2 (a), the light of the three colors R, G, and B separated by the color separation element 9 is approximately the same optical distance on the optical path. To the reflecting surface of the polygon mirror 13 and reflected there, and then a single plate reflection type image through the third imaging lens group, the 1 / 2λ wavelength plate 5a, the PBS 18, and the 1 / 4λ wavelength plate 5c. The display element 12 reaches the pixel areas of R, G, and B colors. Therefore, each color light reflected / bent on the reflecting surface of the rotating polygon mirror 13 is reflected under substantially the same conditions, and is substantially uniformly incident on the pixel area of each color of the single-plate reflective image display element 12. It is thought that it will do.

In addition, FIG. 2 of the accompanying drawings shows the positions at which the light of the three colors R, G, and B is incident on the reflecting surface of the polygon mirror 13 that is a reflective rotating polyhedron. In this figure, the rotation center of the polygon mirror 13 is indicated by “O”, and the dotted line drawn horizontally from the rotation center O is “0 °”. In addition, an angle formed by a perpendicular drawn from the center of rotation with respect to the reflecting surface and the dotted line is denoted by “θ”. Polygon deflection angle regions for each color of R, G, and B, θR, θG, and θB are set so as to satisfy the following conditions.
In (a), (b), and (c) of FIG. 2, θR: θR1 ≦ θR ≦ θR2
θG: θG1 ≦ θG ≦ θG2
θB: θB1 ≦ θB ≦ θB2
In the case of G color, θG1 is set to ± a °, where the position of the R color light that first switches to the next reflecting surface with the rotation of the polygon mirror 13 in the direction of the arrow in FIG. When the difference angle with the position of the G color light that switches to the next reflecting surface is `` α '',
θR: −a + α ≦ θR ≦ + a + α
θG: −a ≦ θG ≦ + a
θB: −a−α ≦ θB ≦ + a−α
However, (theta) 1- (theta) 3 represents the area | region of the rotation angle of the said rotation polyhedron corresponding to each color light, and (alpha) is the deflection angle ((color light) of center color light among the three colors light irradiated on the said reflective surface (). In the above case, G color light is mainly used to reduce the ambient illumination ratio on the panel and the color unevenness area, but this is not restrictive.) Rotation angle of the rotating polyhedron of other color light Indicates the amount of misalignment.

  According to the setting in the optical unit described above, in particular, the relationship between the reflection surface of the polygon mirror 13 and the light of the three colors R, G, and B, as shown in FIG. The light of the three colors R, G, and B separated by the element 9 and then incident substantially perpendicularly to the reflecting surface of the polygon mirror 13 which is a reflection type rotating polyhedron is reflected on the surface under substantially the same conditions. The light is reflected and bent, and reaches the pixel regions of the R, G, and B colors of the single-plate reflective image display element 12 through the above-described tertiary imaging system. As a result, as shown in FIG. 3B, the single-plate reflective video display element 12 of each color of R, G, and B that moves in a certain direction as the polygon mirror 13 rotates in the arrow direction. The amount of movement (scanning) on the surface is almost equal. That is, the available area on the single-plate reflective image display element 12 is increased, and the utilization efficiency can be increased. Note that the horizontal axis in FIG. 3B indicates the position L on the surface of the single-plate reflective video display element 12.

  On the other hand, in the optical unit disclosed in the above-described prior art, the light separated into the three colors R, G, and B by the color separation means is projected onto the reflecting surface of the rotating polygon mirror 13 with an inclination. However, in this case, as shown in FIG. 4A, each color light has a position on the optical path where the light is reflected and bent (“dR” and “dG” in the figure) depending on the position on the reflection surface. , See “dB”). Therefore, as shown in FIG. 4B, when the light is subsequently incident on the pixel area of each color of the single-plate reflective image display element 12, the amount of scan in the incident area does not match, and thus the obtained image It is considered that the brightness of each color differs in this and the balance is lost.

  That is, in the present invention, as described above, the secondary imaging system including the secondary imaging lens group 25 and the PBS 10 for guiding the separated light onto the reflecting surface of the polygon mirror 13 is separated. When light of three colors R, G, and B is projected onto the reflecting surface of the rotating polygon mirror 13, each color light is incident on the reflecting surface at an angle of approximately perpendicular (90 °). It is configured. According to such a configuration, the scan amount of each color light incident on the pixel region on the single-plate reflective image display element 12 is made uniform, thereby eliminating the problem caused by the difference in brightness of each color, An excellent projection image can be obtained.

  In addition to the above-described reflective liquid crystal panel (LCOS), the single-plate reflective video display element 12 includes a transmissive liquid crystal panel (LCD), a ferroelectric liquid crystal panel (FLC), and a digital micromirror. There are mold panels, etc., but in the present invention, any of these panels can be used as appropriate. In particular, the present embodiment shows an example in which LCOS, LCD, or FLC is used as the single-plate reflection type image display element 12.

  Next, FIG. 5 shows a configuration of an optical unit of a video display apparatus according to another embodiment of the present invention. In this other embodiment, in the basic structure shown in FIG. 1, in particular, a secondary connection that irradiates the polygon mirror 13 with light of three colors R, G, and B separated by the color separation element 9. By making the image system common with the tertiary imaging system for guiding the three colors of light reflected by the polygon mirror 13 to the single-plate reflective image display element 12, the entire apparatus can be reduced in size and weight. Is intended.

  That is, as is clear from FIG. 5, random polarized light obtained from the light source 1 through the reflector 2 is given polarized light (S-polarized light in this example) by the polarization conversion element 4 and the light pipe 3. And is guided to a color separation element 9 directly connected to the output opening of the light pipe 3, where it is separated into light of three colors R, G, and B. Thereafter, the light is incident on the PBS 18 through a primary imaging system including a plurality of lenses 6 and 7. Note that the primary imaging system composed of these lenses 6 and 7 can be omitted, and in that case, it is further advantageous for reducing the size and weight of the apparatus.

  Thereafter, the three colors of light (S-polarized light) separated by the color separation element 9 are reflected by the action of the PBS 18, and the quarter-wave plate 4a and the lenses 16 and 15 constituting the secondary imaging system. , And 14 so as to be incident at an angle of substantially perpendicular (90 °) to the reflecting surface of the rotating polygon mirror 13, and in the vicinity of the reflecting surface of the polygon mirror 13 (reflecting surface It is the same as the above that it is formed so as to be formed as a plurality of secondary light source images around several millimeters). Thereafter, the three colors of light reflected by the reflecting surface of the polygon mirror 13 are converted into a tertiary imaging system that is configured in common by the lenses 14, 15, and 16 constituting the secondary imaging system. The light again enters the PBS 18 through the quarter-wave plate 4a (P-polarized light), passes therethrough, and is irradiated onto the single-plate reflective image display element 12. That is, as a result, light of three colors R, G, and B moving at a constant speed in a predetermined direction is incident on different areas on the single-plate reflective video display element 12, and the reflected three colors The light (S-polarized light) is again reflected by the PBS 18 and enters the projection lens 23 via the polarizing plate 17b. As a result, the light of the three colors R, G, and B modulated on the single-plate reflective image display element 12 is enlarged and projected, and displayed on the screen as described above.

  Further, FIG. 6 shows a modified example of the optical unit for the video display device shown in FIG. In this modified example, as is apparent from the figure, in the configuration shown in FIG. 5, random polarized light obtained from the light source 1 via the reflector 2 is once incident on the polarization conversion element 4. It is guided to a light pipe or light funnel 27 which is a light guide attached to the mouth, and the emission angle is adjusted so that a desired F value is obtained. Thereafter, in the same manner as described above, the polarization conversion element 4 aligns the polarization direction with either S-polarized light or P-polarized light, and then the light is guided to the light pipe 3. According to this configuration, the randomly polarized light obtained from the light source 1 through the reflector 2 is once guided to the light pipe 27 and adjusted for the emission angle, and then enters the polarization conversion element 4. Since the polarization directions are aligned, the efficiency of the polarization conversion element 4 can be improved, and a brighter image can be obtained.

  Further, in this modified example, instead of the color separation element 9 for separating the light of the three colors R, G, and B connected to the rear end of the light pipe 3 in FIG. 5, in addition to the above R, G, and B, Furthermore, a brighter image can be obtained by adopting the color separation element 9 ′ that can separate and extract white (W) light. In this modification, the four-color light beams separated by the color separation element 9 'are reflected by the PBS 10 and guided to the PBS 18 through the plurality of lenses 6 and 7 constituting the primary imaging system. However, depending on the arrangement of the color separation element 9 ′, the light pipe 3, etc., the primary image forming system composed of the PBS 10 and the lenses 6 and 7 can be omitted. It would be even more advantageous for conversion. Further, in this modified example, in addition to the above R, G, B, the use of the color separation element 9 ′ capable of separating white (W) light causes the four colors reflected by the polygon mirror 13 to pass through the PBS 18. In order to receive light, the single-plate reflective image display element 12 ′ is formed by dividing the light receiving area into four areas as shown in the figure. The secondary imaging system that irradiates the polygon mirror 13 with the light of these four colors (R, G, B, and W), and the four-color light reflected by the polygon mirror 13 is displayed on the single plate reflection type image display. In the same manner as described above, the entire apparatus is reduced in size and weight by being shared with a tertiary imaging system for leading to the element 12 '.

  That is, also in the modified example shown in FIG. 6, the random polarized light obtained from the light source 1 through the reflector 2 is efficiently condensed by the light pipe 27 which is a light means, and the polarization conversion element 4 and the light The light is polarized into predetermined polarized light (S-polarized light in this example) by the pipe 3, and then guided to the color separation element 9 ′ for four-color light, where the light is converted into four colors of light of R, G, B, and W. To be separated. Thereafter, the light is incident on the PBS 18 through the PBS 10 and a plurality of lenses 6 and 7 constituting the primary imaging system. Thereafter, the four colors of light (S-polarized light) separated by the color separation element 9 ′ are reflected by the action of the PBS 18 as described above, and the 1 / 4λ wavelength plate 4a and the secondary imaging system are reflected. It is configured so as to be incident at an angle of substantially perpendicular (90 °) to the reflecting surface of the rotating polygon mirror 13 through the lenses 16, 15, and 14, and the reflection of the polygon mirror 13. It is the same as the above that it is configured so as to be formed as a plurality of secondary light source images in the vicinity of the surface (before and after the reflecting surface, about several mm).

  Thereafter, the four colors of light reflected by the reflecting surface of the polygon mirror 13 are combined with the tertiary imaging system that is configured in common by the lenses 14, 15, and 16 that constitute the secondary imaging system. The light again enters the PBS 18 through the quarter-wave plate 4a (P-polarized light), passes therethrough, and is irradiated onto the single-plate reflective image display element 12 ′. That is, by this, four colors of light of R, G, B, and W that move at a constant speed in a predetermined direction are incident on different areas on the single-plate reflective image display element 12 ′, and the reflection The four colors of light (S-polarized light) are reflected again by the PBS 18 and enter the projection lens 23 via the polarizing plate 17b. As a result, the light of the four colors R, G, B, and W modulated on the single-plate reflective image display element 12 'is enlarged and projected and displayed on the screen as described above.

  In this modification, as described above, a brighter image can be obtained as the entire apparatus is reduced in size and weight.

  Next, FIG. 7 shows a modification of the optical unit shown in FIG. That is, in this modification, as is apparent from the drawing, in particular, the light collecting portion including the light pipe 27, the polarization conversion element 4, and the light pipe 3 shown in FIG. The arrangement of the polarization conversion element 4 and the light pipe 3 is reversed. That is, according to such a configuration, the polarization conversion element 4 is arranged at a distance from the light source 1 that is also a heat generation source, and the light collected from the light source 1 by the light pipe 3 is polarized with a large F value. Is incident on. As a result, the polarization conversion element 4 whose characteristics are likely to change due to heat is protected from heating by the light source 1, so that the conversion characteristics of the polarization conversion element 4 are ensured and the light from the light valve 3 is converted to the polarization. By entering the element 4 with a large F value, the conversion efficiency can be improved.

  In the modification shown in FIG. 7 as well, random polarized light obtained from the light source 1 via the reflector 2 is efficiently condensed by the light pipe 3 that is a light means, and is predetermined by the polarization conversion element 4. Polarized light (in this example, S-polarized light) and then guided to a color separation element 9 ′ for four-color light, where it is separated into four-color light of R, G, B, and W. Thereafter, the light is incident on the PBS 18 through the PBS 10 and a plurality of lenses 6 and 7 constituting the primary imaging system. Thereafter, the four colors of light (S-polarized light) separated by the color separation element 9 ′ are reflected by the action of the PBS 18 as described above, and the 1 / 4λ wavelength plate 4a and the secondary imaging system are reflected. It is configured so as to be incident at an angle of substantially perpendicular (90 °) to the reflecting surface of the rotating polygon mirror 13 through the lenses 16, 15, and 14, and the reflection of the polygon mirror 13. It is the same as the above that it is configured so as to be formed as a plurality of secondary light source images in the vicinity of the surface (before and after the reflecting surface, about several mm).

  Thereafter, the four colors of light reflected by the reflecting surface of the polygon mirror 13 are combined into a tertiary imaging system that is configured in common by the lenses 14, 15, and 16 that constitute the secondary imaging system. Then, the light again enters the PBS 18 (P-polarized light) through the ¼λ wavelength plate 4a, passes through it, and is irradiated onto the single-plate reflective video display element 12 ′. That is, by this, four colors of light of R, G, B, and W that move at a constant speed in a predetermined direction are incident on different areas on the single-plate reflective image display element 12 ′, and the reflection The four colors of light (S-polarized light) are reflected again by the PBS 18 and enter the projection lens 23 via the polarizing plate 17b. As a result, the light of the four colors R, G, B, and W modulated on the single-plate reflective image display element 12 'is enlarged and projected and displayed on the screen in the same manner as described above.

  By the way, in the above-mentioned various embodiments and modifications thereof, as described above, the light from the light source 1 is converted into S-polarized light or P-polarized light by the action of the polarization conversion element 4, and thereafter In the optical path, a polarizing element is used to control reflection and transmission of the polarized light, thereby forming a predetermined optical path. However, the present invention is not limited to such a configuration. For example, as shown by the following other embodiments, an optical unit for an image display apparatus can be configured without using polarized light. is there.

  First, FIG. 8 shows an example of the structure of an optical unit that employs a so-called total reflection prism (or twin total reflection prism) 25, but does not use a polarization conversion element as its component. In this embodiment, as shown in the figure, the light obtained from the light source 1 is guided to the light pipe 3 via the reflector 2, but in this example, the light pipe 3 has an ultraviolet ray at the entrance. A UV cut filter 11 for protecting from (UV) is provided. The light condensed by the light pipe 3 is guided to the color separation element 9 directly connected to the output opening of the light pipe 3, where it is separated into light of four colors R, G, B, and W. . Thereafter, the light is incident on the total reflection mirror 10 'through the lens 6 constituting the primary imaging system and reflected, and is incident on the total reflection prism 25 via the lens 7 constituting the primary imaging system. To do. In this case as well, the primary imaging system constituted by the lenses 6 and 7 can be omitted, and in that case, it will be more advantageous for reducing the size and weight of the apparatus.

  In this other modification, the light of the four colors R, G, B, and W separated on the first boundary surface (right side in the figure) of the total reflection prism 25 has its critical angle (for example, , 41 °), and therefore reflected at the interface, and further reflected through the lenses 16, 15, and 14 constituting the secondary imaging system and rotating at a predetermined angular velocity. The light enters the polygon mirror 13 which is a mold rotating polyhedron. The four colors R, G, B, and W reflected on the reflecting surface of the polygon mirror 13 pass through the lenses 14, 15, and 16 constituting the secondary imaging system again, and the total reflection prism. The incident angle at this time is set so as not to exceed the above-mentioned critical angle. Therefore, as shown in the figure, four of R, G, B, and W reflected by the polygon mirror 13 are shown. The colored light passes through the total reflection prism 25 (first boundary surface) and is incident on different areas on the single-plate reflective image display element 12 ′. Thereafter, the four colors of light reflected by the single-plate reflective image display element 12 ′ are incident on the total reflection prism 25 again, but the display element is disposed slightly inclined. The light is reflected at the second boundary surface (left side in the figure) and enters the lens 23. Thereafter, the projection is performed on the screen (not shown) through the projection lens 23 in the same manner as described above.

  Note that, in the optical unit according to another modified example, as in the above-described embodiment, the lenses 16 and 15 that reflect on the first boundary surface of the total reflection prism 25 and constitute the secondary imaging system. , 14 and the four colors of light R, G, B, and W that are incident on the polygon mirror 13 are also configured to be incident at an angle substantially perpendicular (90 °) to the reflecting surface. In addition, a plurality of secondary light source images are formed in the vicinity of the reflection surface of the polygon mirror 13 (before and after the reflection surface, about several mm). However, as is apparent from the drawing, in the optical unit according to another modified example, the arrangement direction of the polygon mirror 13 and the single-plate reflection type image display element 12 ′ is 90 ° with respect to the above embodiment. Are arranged differently. It will be apparent to those skilled in the art that the same effect as described above can be obtained by the configuration of the optical unit according to another modified example.

  FIG. 9 shows a modification of the optical unit shown in FIG. As is apparent from the figure, in this modification, a concave lens 24 is provided between the UV cut filter 11 and the light pipe 3, and the light obtained from the light source 1 through the reflector 2 is supplied to the light pipe 3. The F value is increased to improve the light collection efficiency, and a part of the total reflection prism (or twin total reflection prism) 25 that is not used as an optical path (specifically, the upper right part of the figure) is cut off. Therefore, the prism is reduced in size and weight. Note that the operation of the modified example employing the prism 25 'reduced in size and weight is the same as that in FIG. 8, and the description thereof is omitted here. Also, it will be apparent to those skilled in the art that the effects obtained by this modification can be obtained in addition to the above-described reduction in size and weight of the prism and further improvement in light collection efficiency, as well as the above-described effects. .

  Finally, FIG. 10 shows an internal configuration of a video display device including the optical unit according to the present invention described above in various ways. In this example, for example, the optical unit shown in FIG. 7 includes the projection lens 23 in a part of the side wall of the housing inside the housing 100 formed in a substantially box shape by plastic or metal plate. Therefore, it is attached so that an image can be projected to the outside through the projection lens 23. In addition, a power supply for supplying electric power for driving an electric motor (not shown) for rotating and driving the polygon mirror 13 while supplying electric power to the lamp as the light source 1 to a part of the casing 100. Along with the unit 26, a control circuit for controlling the amount of light emitted from the lamp, which is the light source 1, and the power supplied to the motor, and an external signal are inputted and supplied to the single-plate reflective video display elements 12, 12 ′. A video signal processing circuit for generating a video signal and a control unit 28 including, for example, a microprocessor for controlling the entire apparatus including other elements (not shown) are incorporated.

It is a block diagram which shows the detail of the optical unit used as the main components of the video display apparatus which becomes this invention. FIG. 4 is a partially enlarged perspective view for explaining a position where light of three colors R, G, and B is incident on a reflecting surface of a polygon mirror in the optical unit of the present invention. In the optical unit of the present invention described above, the state in which the light of the three colors R, G, and B is reflected by the reflecting surface of the polygon mirror will be described, and the scanning on the single-plate reflection type image display device will thereby be performed. It is a figure explaining the state of. A description will be given of a state in which light of three colors R, G, and B is reflected by the reflection surface of the polygon mirror in the optical unit of the prior art, and the scanning (scanning) on the single-plate reflection type image display device is thereby performed. It is a figure explaining a state. It is a block diagram which shows the detail of the optical unit of the video display apparatus which becomes another Example of this invention. It is a figure which shows the modification of the optical unit of the video display apparatus shown in the said FIG. Furthermore, it is a figure which shows the modification of the optical unit of the video display apparatus shown in the said FIG. It is a block diagram which shows the detail of the optical unit of the image display apparatus which becomes further another Example of this invention. It is a figure which shows the modification of the optical unit of the video display apparatus shown in the said FIG. It is a block diagram which shows the whole structure of the video display apparatus which employ | adopted the optical unit shown above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Rillecta 3 ... Light valve 4 ... Polarization conversion element 5a ... 1/2 (lambda) wavelength plate 5b, 5c ... 1/4 (lambda) wavelength plate 6, 7, 8, 14, 15, 16, 25 ... Lens 9 ... Color separation Element 10: Polarization beam splitter (PBS) 12: Single plate reflection type image display element 13 ... Polygon mirror (reflection type rotating polyhedron) 17b ... Polarizing plate 18 ... Polarization beam splitter (PBS) 23 ... Projection lens

Claims (7)

A light source;
Color separation means for separating light emitted from the light source into a plurality of color lights;
Each color light emitted from the color separation means is incident on a different area, and an image display element that forms an optical image according to the video signal by emission from each area;
A plurality of color lights emitted from the color separation means are irradiated to different areas of the video display element while changing the respective optical axis directions and moving the areas irradiated with the plurality of color lights in a predetermined direction. A rotating polyhedron,
An optical unit including a projection device that projects light emitted from the image display element as an image;
An optical path for guiding a plurality of color lights from the color separation unit to the rotating polyhedron is provided, and the optical path of the plurality of color lights is formed on a single surface constituting the rotating polyhedron at a predetermined angle. An optical unit of an image display device, wherein the optical unit is configured to enter or enter and exit substantially perpendicularly.   The optical unit according to claim 1, wherein the rotating polyhedron is a reflective rotating polyhedron having a surface as a reflecting surface.   3. The optical unit according to claim 2, wherein an optical path for guiding a plurality of color lights from the color separating unit to the rotating polyhedron is further emitted from the color separating unit on a reflecting surface of the reflective rotating polyhedron. An optical unit of an image display device, wherein each color light is incident with a substantially uniform optical length.   3. The optical unit according to claim 2, wherein an optical path for guiding a plurality of color lights from the color separation unit to the rotating polyhedron is such that each color light emitted from a reflecting surface of the reflective rotating polyhedron is the image display. An optical unit of a video display device, wherein the optical unit is configured to uniformly scan the element. 3. The optical unit according to claim 2, wherein an optical path for guiding a plurality of color lights from the color separation unit to the rotating polyhedron has at least three colors of light emitted from the color separation unit under the following conditions: An optical unit of an image display device configured to irradiate on a reflection surface of the reflection type rotating polyhedron so as to satisfy the condition.
θ1: −a + α ≦ θ1 ≦ + a + α
θ2: −a ≦ θ2 ≦ + a
θ3: −a−α ≦ θ3 ≦ + a−α
However, (theta) 1- (theta) 3 represents the area | region of the rotation angle of the said rotation polyhedron corresponding to each color light, and (alpha) is with respect to the deflection angle of center color light among the light of three colors irradiated on the said reflective surface. The amount of deviation of the rotation angle of the rotating polyhedron of other color light is shown.   3. The optical unit according to claim 2, wherein the plurality of color lights are light source images in the vicinity of a reflection surface of the reflective rotary polyhedron on an optical path for guiding the plurality of color lights from the color separation unit to the rotary polyhedron. An optical unit of an image display device, comprising an optical system that forms an image.   Along with the optical unit according to any one of claims 1 to 6, a power supply unit for supplying predetermined power to the light source in the optical unit, and a video signal to the video display element in the optical unit And a video signal processing unit for storing the video signal processing unit in a housing.

Images