JP4867854B2 - Virtual image display device - Google Patents

Description

  The present invention relates to a virtual image display device in which video information projected from an optical unit is reflected by a translucent reflecting means, and the video information is superimposed on a foreground as a virtual image by a reflecting means from a viewpoint.

  In general, this type of virtual image display device reflects video information projected from an optical unit by a translucent reflecting means, and makes the video information visible from the viewpoint as a virtual image by the reflecting means superimposed on the foreground. is there.

  Such virtual image display devices are used in systems that display another display image as a virtual image so as to be superimposed on the image of the monitor installed in front or the scenery in front, and provide information for entertainment such as games and vehicles Useful as a device.

  Regarding the virtual image display device described above, there has been proposed a method in which an image from a display element is projected onto a screen with a projection lens and this image is further magnified with a magnifying lens (Japanese Patent Laid-Open No. 2005-70255).

  However, this method has a problem that the chromatic aberration generated when the image on the screen is magnified by the magnifying lens causes a color shift of the image and significantly deteriorates the display quality.

As a first method for eliminating this color misregistration, a method may be considered in which the magnifying lens is a combination of concave and convex lenses having different chromatic dispersion.
In addition, as a second method of eliminating color misregistration, color misregistration in the direction opposite to that caused by the magnifying lens is generated in the image on the screen, and as a result, color misregistration of the image observed by the observer is corrected What to do is conceivable. Specifically, a displacement lens that is movable in the optical axis direction of the lens is arranged in the projection lens, and the displacement lens is moved in the optical axis direction in conjunction with a rotating wheel equipped with a color filter. A method of changing the magnification has been proposed (see Patent Document 1).
JP 2007-25512 A

  However, the first method has a problem that when the magnifying lens is enlarged, the thickness of the lens increases and the optical unit becomes enormous. When the lens is a Fresnel lens in order to reduce the thickness, moire (interference fringes) is caused. Occurs and the image quality deteriorates.

  In the second method, since the displacement lens is moved in the optical axis direction of the projection lens, a lateral magnification as designed can be obtained after the displacement lens is moved to a predetermined position of each color. Since the predetermined horizontal magnification cannot be obtained during the movement to the color, the horizontal magnification changes and the image becomes blurred. Further, a separate synchronization control means for driving the rotating wheel and the displacement lens in synchronization is required.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a virtual image display device capable of realizing a good image quality with no color misregistration with a simple configuration.

(1) The virtual image display device according to claim 1 displays a display image on the screen by the light beam projected by the projection optical system. Then, this display image is magnified by the magnifying optical system and then reflected by the translucent reflecting means. As a result, the display image is displayed as a virtual image on the opposite side of the reflecting means from the observer's eye point.

  Moreover, the rotation wheel with which the virtual image display apparatus which concerns on Claim 1 is equipped with the several filter part from which the wavelength range of the light to permeate | transmit differs in the circumferential direction, and a rotation wheel rotation means is a plurality of rotation wheels. The rotating wheel is rotated so that any one of the filter units is disposed in the light flux between the display element and the screen by switching in a time division manner. At this time, for example, when the image on the display element is switched to an image corresponding to each color in conjunction with the rotation of the rotation wheel, if the rotation of the rotation wheel is high speed, a virtual image of the color is caused by a human afterimage phenomenon. Is obtained.

In the virtual image display device of the present invention, correction lenses having different focal lengths are formed on the plurality of filter units in the rotating wheel, and images projected on the screen by the projection optical system are displayed for each color by the correction lens. Are corrected (enlarged or reduced) at different magnifications. The magnification of the correction lens is set so as to cancel chromatic aberration when the image is magnified by the magnifying optical system, and a good color virtual image with little chromatic aberration can be obtained when viewed from the observer.
(2) The virtual image display device according to claim 2 displays a display image on the screen by the light beam projected by the projection optical system. Then, this display image is magnified by the magnifying optical system and then reflected by the translucent reflecting means. As a result, the display image is displayed as a virtual image on the opposite side of the reflecting means from the observer's eye point.

  Further, the filter wheel included in the virtual image display device according to claim 2 is provided with a plurality of filter portions having different wavelength ranges of transmitted light in the circumferential direction, and the filter wheel rotating means includes a plurality of filter wheels in the filter wheel. The filter wheel is rotated so that any one of the filter units is switched in a time division manner in the light flux between the display element and the screen. At this time, for example, when the image on the display element is switched to an image corresponding to each color in conjunction with the rotation of the filter wheel, if the filter wheel rotates at a high speed, a virtual image of the color is caused by a human afterimage phenomenon. Is obtained.

The virtual image display device of the present invention further includes a rotating wheel in which correction lenses corresponding to each of the plurality of filter units are arranged in the circumferential direction, and each correction lens in the rotating wheel is synchronized with the corresponding filter unit. The rotating wheel rotating means for rotating the rotating wheel is provided so as to be switched in a time division manner in the light flux between the display element and the screen .

The virtual image display device of the present invention corrects (enlarges or reduces) an image projected on a screen by a projection optical system with a different magnification for each color by a correction lens provided on a rotating wheel. The magnification of the correction lens is set so as to cancel chromatic aberration when the image is magnified by the magnifying optical system, and a good color virtual image with little chromatic aberration can be obtained when viewed from the observer.
(3) In the invention according to claim 3, the screen size of the virtual image is different between the vertical direction and the horizontal direction, and the correction lens has a magnification in the longitudinal direction between the vertical direction and the horizontal direction of the virtual image. It is a cylindrical lens.

When the screen size is different between the vertical and horizontal directions, the color shift tends to be severe in the longitudinal direction of the screen (for example, the horizontal direction). In the present invention, the longitudinal chromatic aberration is corrected by a cylindrical lens having a magnification in the longitudinal direction. Therefore, it is possible to effectively reduce chromatic aberration with the minimum necessary component configuration.
(4) The invention according to claim 4 reduces the chromatic aberration in one direction in the virtual image by the correction lens provided in the first rotating wheel, and the one in the virtual image by the correction lens provided in the second rotating wheel. Chromatic aberration in a direction orthogonal to the direction can be reduced. Therefore, the effect of suppressing chromatic aberration is even higher.

In the present invention, the correction lens provided in the first rotation wheel and the correction lens provided in the second rotation wheel can be set arbitrarily. For example, even when the magnification of the magnifying optical system is different between the vertical direction and the horizontal direction, the curvature of the correction lens in the first rotation wheel and the second rotation wheel is changed between the vertical direction and the horizontal direction according to the difference in magnification. Can be changed. As a result, the effect of suppressing chromatic aberration is even higher.
(5) The invention according to claim 5 has a radial cylindrical lens having a magnification in the radial direction of the rotating wheel as the correction lens, so that the magnification of the light beam can be easily controlled and chromatic aberration can be corrected.
(6) In the invention according to claim 6, the correction lens is formed only on one side of the rotating wheel. By doing so, it is possible to reduce labor and cost required for forming the correction lens.
(7) In the invention which concerns on Claim 7, a rotation wheel is located between the aperture_diaphragm | restriction in a projection optical system, and the projection lens adjacent to a aperture_diaphragm | restriction. At this position, since the width of the light beam becomes small, the rotation wheel can be made small as a result, and as a result, the entire optical system can be made small.
(8) In the invention which concerns on Claim 8, a rotation wheel is located between a display element and a projection lens. Since the width of the light flux is reduced between the display element and the projection lens, the rotation wheel can be reduced, and as a result, the entire optical system can be reduced. In addition, since it is not necessary to integrate the projection lens and the rotating wheel, it is possible to prevent the configuration of the projection lens from becoming complicated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1. First Embodiment (a) Overall Configuration of Virtual Image Display Device and Principle of Displaying Color Virtual Image First, the overall configuration of the virtual image display device 1 will be described with reference to FIG. FIG. 1 is a perspective view showing the configuration of the virtual image display device 1.

The virtual image display device 1 includes a light source 3 that illuminates a display element 5 to be described later, a display element 5 for displaying an image, and a projection lens 7 that projects an image displayed on the display element 5. A system 9 is provided. The virtual image display device 1 includes a rotating wheel 11, a screen 13, a magnifying lens 15, and a combiner (half mirror) 17.
A screen 13 is disposed at the image forming position of the display element 5 projected by the projection lens 7. The display image by the projection lens 7 is magnified by the magnifying lens 15, reflected by the combiner 17, and projected as a virtual image 21 from the observer's eye point (right eye and left eye) 19 on the opposite side of the combiner 17. . The screen 13 is made of a translucent surface having a diffusing surface, for example, a plastic such as acrylic, or a glass material.

Next, the configuration around the projection lens 7 and the rotating wheel 11 will be described with reference to FIGS. 2 and 3 are explanatory views showing the configurations of the projection lens 7 and the rotating wheel 11, in which FIG. 2 is a cross-sectional view taken along the yz plane in FIG. 1, and FIG. 3 is a cross-sectional view taken along the zx plane in FIG. FIG. FIG. 4 is a plan view showing the rotating wheel 11.
1, the x-axis direction is parallel to the horizontal direction (longitudinal direction) on the screen 13, the y-axis is parallel to the vertical direction on the screen 13, and the z-axis is a light beam projected by the projection optical system 9. It is set so as to be parallel to the optical axis 25. Then, both the coordinate in the x-axis direction and the coordinate in the y-axis direction of the optical axis 25 are set to 0 mm.
As shown in FIGS. 2 and 3, the projection lens 7 includes four lenses 7a, 7b, 7c, and 7d, and is housed in a housing (not shown) in FIGS.
The rotating wheel 11 is attached between the lens 7a and the lens 7d as shown in FIGS. In the projection lens 7, the lens 7 a is a lens adjacent to the diaphragm 18, and the rotating wheel 11 is located between the lens 7 a and the diaphragm 18.
The rotating wheel 11 has a disk shape with a diameter of 40 mm, and its direction is a direction in which the main plane is parallel to the xy plane (a direction orthogonal to the optical axis 25 of the projection lens 7). The rotation shaft 23 of the rotary wheel 11 is arranged so that the coordinate in the x-axis direction is −14 mm and the coordinate in the y-axis direction is 0 mm.

As shown in FIG. 4, the rotating wheel 11 is divided into three regions, that is, a blue region 11a, a green region 11b, and a red region 11c. A color filter that selectively transmits blue light is formed in the blue region 11a, a color filter that selectively transmits green light is formed in the green region 11b, and a red color filter is formed in the red region 11c. A color filter that selectively transmits light is formed.
The rotating wheel 11 is driven to rotate by a motor (not shown) around the rotating shaft 23. Then, any one of the three regions (blue region 11a, green region 11b, and red region 11c) of the rotating wheel 11 is switched in a time division manner so as to cross the optical axis 25.
At this time, the image on the display element 5 is switched to an image corresponding to each color in conjunction with the rotation of the rotary wheel 11 (that is, the time zone in which the optical axis 25 passes through the blue region 11a is blue on the display element 5). The time zone in which the optical axis 25 passes through the green region 11b is displayed on the display element 5 and the time zone in which the optical axis 25 passes through the red region 11c is displayed. When the rotating wheel 11 rotates at high speed, a color virtual image 21 is obtained due to the afterimage phenomenon of humans.

(B) Configuration for canceling out chromatic aberration As shown in FIGS. 4 and 5, a radial cylindrical lens 27 is formed on the circumference of the rotating wheel 11 on the circumference having a distance of 14 mm from the rotating shaft 23. . 5A is a sectional view in the radial direction of the rotating wheel 11 in the blue region 11a, and FIG. 5B is a sectional view in the radial direction of the rotating wheel 11 in the green region 11b. (C) is sectional drawing in the radial direction of the rotating wheel 11 in the red area | region 11c.
The radial cylindrical lens 27 has a predetermined curvature as shown in FIG. 5A when viewed in a cross section along the radial direction of the rotating wheel 11 in the blue region 11a, and in the green region 11b. When viewed in a cross section along the radial direction of the rotating wheel 11, as shown in FIG. 5B, it has no curvature, and in the red region 11c, along the radial direction of the rotating wheel 11. When viewed in cross section, as shown in FIG. 5 (c), it has a curvature opposite to that of the blue region 11a. Further, the radial cylindrical lens 27 does not have a curvature in any region when viewed in a cross section along the circumferential direction of the rotating wheel 11.

  As described above, the rotation axis 23 of the rotary wheel 11 is at a position where the coordinate in the x-axis direction is −14 mm and the coordinate in the y-axis direction is 0 mm, and the optical axis 25 is in the coordinates in the x-axis direction and the y-axis direction. Are both at the position of 0 mm, the portion of the radial cylindrical lens 27 on the optical axis 25 extends along the y-axis direction. Therefore, the direction in which the radial cylindrical lens 27 has a curvature on the optical axis 25 is the x-axis direction. By the way, the image displayed on the virtual image display device 1 has a larger size in the x-axis direction than a size in the y-axis direction as shown in the images displayed on the screen 13 and the magnifying lens 15 in FIG. The x-axis direction is the longitudinal direction). As described above, since the radial cylindrical lens 27 has a curvature in the x-axis direction on the optical axis 25, it has a function of enlarging or reducing the image in the longitudinal direction of the image.

The curvature of the radial cylindrical lens 27 is set so as to cancel out chromatic aberration in the x-axis direction. That is, since the magnification magnified by the magnifying lens 15 varies depending on the wavelength of the light beam, the chromatic aberration occurs between the blue light beam, the green light beam, and the red light beam in the virtual image 21 as it is, but the radial cylindrical lens 27 Is set so as to cancel out the chromatic aberration, the chromatic aberration can be eliminated or reduced. The curvature of the radial cylindrical lens 27 that eliminates chromatic aberration can be set by a known method based on the specifications of the projection lens 7 and the magnifying lens 15.
For example, when the specifications of the projection lens 7 and the magnifying lens 15 are those shown in Tables 1 and 2, respectively, the specifications of the radial cylindrical lens 27 are set as shown in Table 3 by a known method. Can do. Note that “Radius” in Table 3 is a value of the cylindrical lens surface acting only in the x-axis direction.

(C) Measurement of chromatic aberration It is shown below that the virtual image display device 1 can cancel chromatic aberration.
The coordinates of a predetermined point on the display element 5 are (xo, yo). The coordinates of the point projected on the screen 13 by the projection lens 7 are (xs, ys). Furthermore, the image on the screen 13 is magnified by the magnifying lens 15, and the coordinates of the point where the image is formed as a virtual image on the surface on which the virtual image 21 is displayed (surface 2 m from the observer, hereinafter referred to as “virtual image surface”) , (Xv, yv).
The coordinates (xo, yo) are the same for any color, and the distance between the coordinates (xv, yv) when the blue light beam is used and the coordinates (xv, yv) when the green light beam is used is d. (B−G), the distance between the coordinates (xv, yv) when the green light beam is used and the coordinates (xv, yv) when the red light beam is used is d (G−R), and the red color The distance between the coordinates (xv, yv) when using the luminous flux of 4 and the coordinates (xv, yv) when using the blue luminous flux is assumed to be d (RB). The wavelengths used for the calculation are 486 nm for blue (B), 587 nm for green (G), and 656 nm for red (R). As d (B−G), d (G−R), and d (R−B) are smaller, the chromatic aberration is smaller.

  Table 4 shows the measurement results of d (BG), d (GR), and d (RB) in the virtual image display device 1. In addition, the measurement was performed about each of three types (xo, yo) (data 1-3).

  As shown in Table 4, the image formation position (xs, ys) on the screen 13 is greatly different depending on the color, and this functions to correct chromatic aberration due to the magnifying lens 15, and as a result, d (BG) , D (GR), d (RB) had a maximum value of only 3.470 mm. As a result, it was difficult for the observer to feel color blur and a good image could be obtained.

Since the virtual image display device 1 uses only one rotating wheel 11, an increase in the manufacturing cost of the virtual image display device 1 can be suppressed as much as possible. Furthermore, although the chromatic aberration tends to increase as the size of the image increases, the rotating wheel 11 has an action of correcting the chromatic aberration in the longitudinal direction (x direction) of the display image, so that the chromatic aberration can be effectively suppressed.
As a comparative example, as shown in FIG. 6, the basic structure is the same as that of the virtual image display device 1, but the position of the rotating wheel 11 is between the light source 3 and the display element 5, and the rotating wheel 11 has a radial shape. Table 5 shows the results of measuring d (BG), d (GR), and d (RB) using the virtual image display device 101 on which the cylindrical lens 27 is not formed. The configuration of the projection lens 107 of the virtual image display apparatus 101 is shown in FIG. 7, and the specifications of the lenses A to E constituting the projection lens 107 are shown in Table 6.

As shown in Table 5, the image formation position (xs, ys) on the screen 13 is not different depending on the color, but the virtual image position (xv, yv) is different for each color due to the influence of chromatic aberration caused by the magnifying lens 15. Greatly different. That is, the maximum values of d (B−G), d (G−R), and d (R−B) are as large as 10.642 mm, and the observer feels a clear color blur, I felt the quality was low.
(D) Effects exhibited by the virtual image display device 1 The virtual image display device 1 according to the first embodiment can exhibit the following effects.

  (i) The image enlarged and projected on the screen 13 by the projection lens 7 is projected with a different lateral magnification for each color by the radial cylindrical lens 27 provided on the rotating wheel 11, and this image is enlarged by the magnification lens 15. Since the chromatic aberration is corrected at the time of viewing, a good image without chromatic aberration can be obtained from the viewpoint of the observer.

In particular, since the chromatic aberration of the image increases as the screen size increases, if the screen size is different between the vertical and horizontal directions, color misregistration tends to become severe in the longitudinal direction of the screen (usually the horizontal direction). In the embodiment, since the chromatic aberration in the longitudinal direction is corrected, the chromatic aberration can be effectively reduced with the minimum necessary component configuration.
(ii) In the first embodiment, since the rotating wheel 11 and the radial cylindrical lens 27 that changes the lateral magnification for each color are integrated, the extra parts are minimized and the configuration is simple. Correction of chromatic aberration can be realized. This integration also has the effect of eliminating the need for an additional control circuit for synchronizing the rotating wheel 11 and the lens that changes the lateral magnification.
(iii) In the first embodiment, since the chromatic aberration is corrected by the radial cylindrical lens 27 provided on the rotating wheel 11, correction of chromatic aberration is performed even when the color of the displayed image changes from one color to another. A state (transition state) that cannot be sufficiently performed does not occur. Therefore, even when the color of the displayed video is switched, chromatic aberration can be corrected and blurring of the video can be prevented.
(iv) In the first embodiment, by using the radial cylindrical lens 27 having a curvature in the radial direction of the rotating wheel 11, the magnification of the light beam can be easily controlled and chromatic aberration can be corrected.
(v) In the first embodiment, a circle connecting the central axes of the radial cylindrical lenses 27 is in contact with the optical axis 25 of the projection lens 7. Thus, since the central axes of the radial cylindrical lens 27 and the projection lens 7 coincide with each other, it is possible to suppress the image from being deformed due to the symmetry of the lens.
(vi) In the first embodiment, the projection lens 7 is composed of a plurality of constituent lenses, and the rotary wheel 11 is positioned between the diaphragm 18 of the projection lens 7 and the constituent lens 7 a adjacent to the diaphragm 18. is doing. Since the aperture 18 of the projection lens 7 reduces the width of the light beam, the rotation wheel 11 can be reduced as a result, and as a result, the entire projection optical system 9 can be reduced.

2. Second Embodiment (a) General Configuration of Virtual Image Display Device and Principle of Displaying Color Virtual Image The configuration of the virtual image display device 1 in the second embodiment is basically the same as that of the first embodiment. However, there are some differences. Below, it demonstrates based on FIGS. 8-10 centering on the difference. FIG. 8 is a perspective view illustrating a configuration of the virtual image display device 1 according to the second embodiment. 9 and 10 are explanatory diagrams showing the configuration around the projection optical system 9 and the rotating wheel 11, in which FIG. 9 is a sectional view in the yz plane, and FIG. 10 is a sectional view in the zx plane. It is.

As shown in FIGS. 9 and 10, the projection lens 7 is composed of three lenses, projection lenses 7a, 7b, and 7c, and is housed in a housing not shown in FIGS. As shown in FIG. 8, the virtual image display device 1 includes two rotating wheels 111 and 112, which are attached between a lens 7a and a lens 7b. In the projection lens 7, the lenses 7 a and 7 b are lenses adjacent to the diaphragm 18, but the rotating wheel 111 is positioned between the diaphragm 18 and the lens 7 a, and the rotating wheel 112 is disposed between the diaphragm 18 and the lens 7 b. To position. The directions of the rotating wheels 111 and 112 are directions in which the main plane is parallel to the xy plane (direction perpendicular to the optical axis 25 of the projection lens 7).
The rotating shaft 123 of the rotating wheel 111 is arranged so that the coordinate in the x-axis direction is −14 mm and the coordinate in the y-axis direction is 0 mm. The rotating shaft 124 of the rotating wheel 112 is arranged so that the coordinate in the x-axis direction is 0 mm and the coordinate in the y-axis direction is 14 mm.
The configuration of the rotating wheels 111 and 112 is the same as that of the rotating wheel 11 in the first embodiment. That is, the rotating wheels 111 and 112 are divided into a blue region, a green region, and a red region.
The rotating wheels 111 and 112 are driven to rotate by motors (not shown) around the respective rotating shafts 123 and 124. Then, one of the three regions (blue region, green region, and red region) in the rotating wheels 111 and 112 is switched and arranged in a time division manner so as to cross the optical axis 25. Here, the rotations of the rotating wheel 111 and the rotating wheel 112 are synchronized so that the colors of the regions crossing the optical axis 25 match. For example, when the blue region of the rotating wheel 111 crosses the optical axis 25, the blue region of the rotating wheel 112 crosses the optical axis 25. The same applies to other regions (colors).

  In conjunction with the rotation of the rotating wheels 111 and 112, the image on the display element 5 is switched to an image corresponding to each color (that is, the time zone in which the optical axis 25 passes through the blue region corresponds to blue on the display element 5). The time zone in which the optical axis 25 transmits the green region is displayed on the display element 5 and the time zone in which the optical axis 25 transmits the red region corresponds to the display element 5 in red. When the rotating wheels 111 and 112 rotate at high speed, a color virtual image 21 is obtained due to a human afterimage phenomenon.

(B) Configuration for canceling out chromatic aberration The rotating wheels 111 and 112 are respectively formed with radial cylindrical lenses 27 as in the rotating wheel 11 in the first embodiment.
As described above, the rotation axis 123 of the rotating wheel 111 is located at a position where the coordinate in the x-axis direction is −14 mm and the coordinate in the y-axis direction is 0 mm, and the optical axis 25 is the coordinate in the x-axis direction and the y-axis direction. Since the coordinates are both 0 mm, the radial cylindrical lens 27 of the rotating wheel 111 extends on the optical axis 25 along the y-axis direction. Therefore, the direction in which the radial cylindrical lens 27 of the rotating wheel 111 has a curvature on the optical axis 25 is the x-axis direction.
The rotation axis 124 of the rotary wheel 112 is at a position where the coordinate in the x-axis direction is 0 mm and the coordinate in the y-axis direction is 14 mm, and the optical axis 25 has both the coordinate in the x-axis direction and the coordinate in the y-axis direction. Since the position is 0 mm, the radial cylindrical lens 27 of the rotating wheel 112 extends on the optical axis 25 along the x-axis direction. Therefore, the direction in which the radial cylindrical lens 27 of the rotating wheel 112 has a curvature on the optical axis 25 is the y-axis direction.
Therefore, the virtual image display device 1 can enlarge or reduce the image in the horizontal direction (x-axis direction) by the rotation wheel 111 and can enlarge or reduce the image in the vertical direction (y-axis direction) by the rotation wheel 112. it can.

The curvature of the radial cylindrical lens 27 in the rotating wheel 111 is set so as to cancel out chromatic aberration in the x-axis direction. Further, the curvature of the radial cylindrical lens 27 in the rotating wheel 112 is set so as to cancel out chromatic aberration in the y-axis direction. Thereby, the chromatic aberration in the x-axis direction and the chromatic aberration in the y-axis direction can be eliminated or reduced. The curvature of the radial cylindrical lens 27 that eliminates chromatic aberration can be set by a known method based on the specifications of the projection lens 7 and the magnifying lens 15.
For example, when the specifications of the projection lens 7 are those shown in Table 7, the specifications of the radial cylindrical lens 27 in the rotating wheels 111 and 112 can be set as shown in Table 8 by a known method. The specifications of the magnifying lens 15 are the same as those in the first embodiment. In Table 8, “Radius” of the rotating wheel 111 is a value of the cylindrical lens surface acting only in the x-axis direction, and “Radius” of the rotating wheel 112 is a value of the cylindrical lens surface acting only in the y-axis direction. It is.

(C) Measurement of chromatic aberration It is shown below that the virtual image display device 1 can cancel chromatic aberration.
The coordinates of a predetermined point on the display element 5 are (xo, yo). The coordinates of the point projected on the screen 13 by the projection lens 7 are (xs, ys). Furthermore, the image on the screen 13 is magnified by the magnifying lens 15, and the coordinates of the point where the image is formed as a virtual image on the surface on which the virtual image 21 is displayed (surface 2 m from the observer, hereinafter referred to as “virtual image surface”) , (Xv, yv).
The coordinates (xo, yo) are the same in any color, and the distance between the coordinates (xv, yv) when the blue light beam is used and the coordinates (xv, yv) when the green light beam is used. d (B−G), and the distance between the coordinates (xv, yv) when the green luminous flux is used and the coordinates (xv, yv) when the red luminous flux is used is d (G−R). The distance between the coordinates (xv, yv) when the red light beam is used and the coordinates (xv, yv) when the blue light beam is used is d (R−B). The wavelengths used for the calculation are 486 nm for blue (B), 587 nm for green (G), and 656 nm for red (R). As d (B−G), d (G−R), and d (R−B) are smaller, the chromatic aberration is smaller.

  Table 9 shows the measurement results of d (BG), d (GR), and d (RB) in the virtual image display device 1.

As shown in Table 9, the imaging position (xs, ys) on the screen 13 differs greatly not only in the x-axis direction but also in the y-axis direction, depending on the color. As a result, the maximum value in d (B−G), d (G−R), and d (R−B) was only 0.176 mm because it serves to correct chromatic aberration in the y-axis direction. This value is only about 1/100 as compared with the case of the comparative example without correction of chromatic aberration. Further, the amount of bleeding is further reduced as compared with the first embodiment. This is because chromatic aberration is corrected not only in the x-axis direction but also in the y-axis direction. As a result, the observer did not feel any color blur and was able to obtain a very good image.
(D) Effects exhibited by the virtual image display device 1 The virtual image display device 1 according to the second embodiment has substantially the same effects as the virtual image display device 1 according to the first embodiment, and further has the following effects. be able to.
(i) Since the virtual image display device 1 can correct both chromatic aberration in the x-axis direction and chromatic aberration in the y-axis direction, the effect of suppressing chromatic aberration is even higher.
(ii) Since the curvature of the radial cylindrical lens 27 included in the rotating wheel 111 and the curvature of the radial cylindrical lens 27 included in the rotating wheel 112 can be arbitrarily set, for example, the lateral magnification of the magnifying lens 15 is set in the vertical direction. Even if the horizontal direction differs, the curvature of the radial cylindrical lens 27 in the rotating wheels 111 and 112 can be changed between the vertical direction and the horizontal direction according to the difference in magnification. As a result, the effect of suppressing chromatic aberration is even higher.

Needless to say, the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the present invention.
In the first embodiment and the second embodiment, the projection lens 7 and the rotating wheel 11 (111, 112) may be provided separately, and the position of the rotating wheel 11 (111, 112) is determined from the display element 5. It can be installed between the screens 13.

In the first embodiment, when the color is changed by synchronizing the rotating wheel 11 and the display element 5, the color of the rotating wheel 11 and the display element 5 are particularly changed at the moment when the color is switched due to a delay of the synchronization circuit or the like. It is possible that the colors do not match perfectly. In this case, as shown in FIG. 11, it is effective to install a black mask 29 between the colors to block the light beam regardless of the wavelength of the light beam. Since the light is shut out by the black mask 29 when the color is switched, even if the color of the rotating wheel 11 and the color of the display element 5 do not completely match, the image viewed by the observer is not affected. . The width of the black mask 29 may be determined in consideration of the delay of the synchronization circuit. Similarly, the black mask 29 can be installed on the rotating wheels 111 and 112 in the second embodiment.
In the first embodiment and the second embodiment, the radial cylindrical lens 27 is a lens having a shape with a different curvature for each color, but a diffractive lens in which a large number of grooves are formed on a flat surface, A Fresnel lens that is an assembly of minute prisms may be used. Further, the lens may be formed only on one side of the rotating wheel 11. By doing so, it is possible to reduce labor and cost required for forming the lens.

  In the first embodiment and the second embodiment, the rotating wheels 11, 111, and 112 may be located between the display element 5 and the projection lens 7. Since the width of the light beam is reduced between the display element 5 and the projection lens 7, the required size of the rotary wheels 11, 111, and 112 is reduced as a result, and the entire optical system can be reduced. Moreover, since it is not necessary to integrate the projection lens 7 and the rotating wheel 11, it can prevent that the structure of a projection lens becomes complicated.

  In the second embodiment, the color filter may be formed on both the rotating wheels 111 and 112, but may be formed on only one of them. If the color filter is formed on only one of them, it is possible to suppress a decrease in the transmittance of the light flux.

  In the first embodiment, instead of the rotating wheel 11, two rotating wheels (filter wheels) 31 and a rotating wheel 33 may be provided as shown in FIG. 12. The rotating wheel 31 is divided into three regions, similarly to the rotating wheel 11, and blue, green, and red color filters are formed on each, but the radial cylindrical lens 27 is not formed. On the other hand, a radial cylindrical lens 27 is formed on the rotating wheel 33 as in the rotating wheel 11, but no color filter is formed. The rotating wheel 31 and the rotating wheel 33 are controlled to rotate in synchronization. That is, when the blue color filter of the rotating wheel 31 is on the optical axis 25, the portion corresponding to blue of the radial cylindrical lens 27 of the rotating wheel 33 is on the optical axis 25. Similarly, when the green and red color filters of the rotating wheel 31 are on the optical axis 25, the corresponding portions of the radial cylindrical lenses 27 of the rotating wheel 33 are on the optical axis 25.

  Since the two rotating wheels 31 and the rotating wheel 33 have the same function as the rotating wheel 11 by combining them, even when the rotating wheel 31 and the rotating wheel 33 are provided, the same as in the first embodiment. There is an effect.

1 is a perspective view showing a configuration of a virtual image display device 1. FIG. FIG. 2 is a cross-sectional view illustrating a projection lens 7 and a rotating wheel 11 in the yz plane of FIG. 1. It is sectional drawing showing the projection lens 7 and the rotary wheel 11 in zx plane of FIG. FIG. 3 is a plan view showing a rotating wheel 11. (A) is sectional drawing in the radial direction of the rotating wheel 11 in the blue area | region 11a, (b) is sectional drawing in radial direction of the rotating wheel 11 in the green area | region 11b, (c) is in red area | region 11c. FIG. 3 is a cross-sectional view of the rotating wheel 11 in the radial direction. It is a perspective view which shows the structure of the virtual image display apparatus in a comparative example. It is sectional drawing showing the projection lens 7 in a comparative example. 1 is a perspective view showing a configuration of a virtual image display device 1. FIG. It is sectional drawing showing the projection lens 7 and the rotation wheels 111 and 112 in yz plane. It is sectional drawing showing the projection lens 7 and the rotation wheels 111 and 112 in zx plane. FIG. 3 is a plan view showing a rotating wheel 11. 1 is a perspective view showing a configuration of a virtual image display device 1. FIG.

Explanation of symbols

1, 31, 33, 101 ... virtual image display device, 3 ... light source, 5 ... display element,
7, 107 ... projection lens, 7a, 7b, 7c, 7d ... lens,
9 ... projection optical system 11, 111, 112 ... rotating wheel, 11a ... blue region, 11b ... green region, 11c ... red region, 13 ... screen,
15 ... Magnifying lens, 17 ... Combiner, 18 ... Aperture,
19 ... eye point, 21 ... virtual image, 23, 123, 124 ... rotation axis,
25 ... Optical axis, 27 ... Radial cylindrical lens, 29 ... Black mask

Claims (8)

A projection optical system comprising: a display element for displaying an image; a light source that illuminates the display element; and a projection lens that projects an image displayed on the display element;
A screen disposed at an imaging position of a light beam projected by the projection optical system;
A magnifying optical system for magnifying the image on the screen;
Translucent reflecting means for reflecting the light beam projected by the magnifying optical system;
A rotating wheel disposed in a circumferential direction with a plurality of filter portions having different wavelength ranges of light to be transmitted;
Rotating wheel rotating means for rotating the rotating wheel so that any one of the plurality of filter units in the rotating wheel is disposed in the light flux between the display element and the screen in a time-sharing manner.
With
A virtual image display device in which the video is visually recognized by being superimposed on a foreground as a color virtual image by the reflecting means from the viewpoint of an observer,
Correction lenses having different focal lengths are formed on the plurality of filter portions in the rotating wheel according to the wavelength of light transmitted by each filter portion so as to cancel out chromatic aberration generated in the magnifying optical system. A virtual image display device characterized by the above. A projection optical system comprising: a display element for displaying an image; a light source that illuminates the display element; and a projection lens that projects an image displayed on the display element;
A screen disposed at an imaging position of a light beam projected by the projection optical system;
A magnifying optical system for magnifying the image on the screen;
Translucent reflecting means for reflecting the light beam projected by the magnifying optical system;
A filter wheel disposed in a circumferential direction with a plurality of filter portions having different wavelength ranges of transmitted light; and
A filter wheel rotating means for rotating the filter wheel so that any one of the plurality of filter units in the filter wheel is switched and arranged in the light flux between the display element and the screen in a time-sharing manner;
With
A virtual image display device in which the video is visually recognized by being superimposed on a foreground as a color virtual image by the reflecting means from the viewpoint of an observer,
A rotating wheel in which a correction lens corresponding to each of the plurality of filter units is arranged in a circumferential direction;
The rotating wheel is arranged so that each correction lens in the rotating wheel is switched in a time-sharing manner in the light flux between the display element and the screen in synchronization with the corresponding filter unit. A rotating wheel rotating means for rotating;
Each of the correction lenses has a different focal length so as to cancel out chromatic aberration generated in the magnifying optical system in accordance with the wavelength of light transmitted by the corresponding filter unit. . The screen size of the virtual image is different in the vertical direction and the horizontal direction,
The virtual image display device according to claim 1, wherein the correction lens is a cylindrical lens having a magnification in a longitudinal direction of the vertical direction and the horizontal direction in the virtual image. The rotating wheel includes a first rotating wheel and a second rotating wheel,
The correction lens provided in the first rotating wheel is a cylindrical lens having a magnification in one direction in the virtual image,
3. The virtual image display device according to claim 1, wherein the correction lens provided in the second rotating wheel is a cylindrical lens having a magnification in a direction orthogonal to the one direction in the virtual image.   The virtual image display device according to claim 1, wherein the correction lens is a radial cylindrical lens having a magnification in a radial direction of the rotating wheel.   The virtual image display device according to claim 1, wherein the correction lens is formed only on one surface of the rotating wheel.   The virtual image display device according to claim 1, wherein the rotating wheel is positioned between a diaphragm in the projection optical system and the projection lens adjacent to the diaphragm.   The virtual image display device according to claim 1, wherein the rotating wheel is located between the display element and the projection lens.