JP2005250232A - Optical path displacing element, optical scanning means, and projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical path displacing element, an optical scanning means, and a projection type image display device such that noise in device operation is reduced with simple constitution, luminance unevenness of projection video is reduced, and focus vibration is suppressed to improve the quality of the video. <P>SOLUTION: The device is equipped with the optical scanning means 101 which makes an optical scan through an annular prism 9 as the optical path displacing element, and further equipped with a white light source lamp 1, a lens 2, dichroic mirrors 3, 4, and 5 which separate a light into R, G, and B, rods 6, 7, and 8 for diffusion shaping which projects the separated lights R, G, and B on the annular prism 9, a rotating means 9c of rotating the annular prism 9, a projection lens 10, reflecting mirrors 12 and 13, an optical modulating element 11, and a projection optical system 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical path displacement element, an optical scanning unit, and a projection type image display apparatus, and more particularly, to an optical path transition element used in a color scroll scanning type projection type image display apparatus and an optical scanning unit using the optical path transition element. And a projection-type image display device.

  A projection-type image display apparatus that projects light from a light source onto a screen via a light modulation element such as a digital mirror device (hereinafter referred to as DMD) or a liquid crystal display element (hereinafter referred to as LCD). A method using three light modulation elements (hereinafter referred to as a three-plate method) and a method using one light modulation element (hereinafter referred to as “three-plate method”) for generating three types of images corresponding to the primary colors (R, G, B). , Referred to as a single plate method).

As shown in FIG. 19, the three-plate system uses dichroic mirrors, filters, cubes, and the like for light from a light source, and is red (hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as G). (Hereinafter referred to as B)), the separated light beams R, G, and B are incident on the three light modulation elements 119r, 119g, and 119b, respectively. An image is formed on the screen 120.
The R, G, and B images are reflected or transmitted through the light modulation elements 119r, 119g, and 119b, and then are aligned and color-combined using the mirror 113, the projection optical system 114, and the like, and projected onto the screen 120.

  In the single plate method, when an LCD is used as a light modulation element, generally, as shown in FIG. 20, one pixel is formed by three small pixels in which an R filter, a G filter, and a B filter (not shown) are arranged. Each small pixel is configured to be a light modulation element 129 that controls reflection, absorption, and transmission of incident light. In this case, of the light emitted from the light source, the light transmitted through the polarizing plate of the LCD light modulation element is transmitted or absorbed through the R, G, B filter, and the component transmitted or reflected through the liquid crystal layer is again applied to the polarizing plate. When transmitted, an R image, a G image, and a B image are simultaneously formed on the screen 120.

  In such a single plate method, small pixels of the separated light beams R, G, and B are displayed on the screen 120, but the small pixels of R, G, and B are visually within a resolution or less. Due to the arrangement, the image is an illusion of spatial synthesis.

  However, in the single plate method described above, since light modulation is performed independently for each small pixel, miniaturization and high definition of the switch element are disadvantageous, so that the size of the light modulation element itself can be reduced. There was a problem that it was difficult.

  In addition, the ratio of the area where the non-wiring black mask that cannot emit light is formed between the adjacent small pixels is increased, and in the color filter, the light incident on the R filter is other than the R component. Since the components, that is, the G and B lights are absorbed, there is a problem that the light utilization rate becomes 1/3 or less of the light emitted from the light source only on the color filter.

  On the other hand, the three-plate method has advantages in that it is easy to achieve high-definition images and high light utilization efficiency compared to the single-plate method, but on the other hand, three light modulation elements 119r, 119g, and 119b are arranged. In addition, since the traveling light paths of the separated light beams R, G, and B are independent, the number of light modulation elements is increased and the cost is increased compared to the single plate method, and the structure of the optical system is complicated and shaped. There is a problem that becomes larger.

  For this reason, in recent projection type image display devices that are required to be reduced in size and cost, the separated light beams R, G, and B are sequentially projected onto the light modulation element in a time-sharing manner, and the light modulation element projects the projected light. “Color Sequential Method” for creating and projecting an image according to the type of light, or simultaneously projecting R, G, B light to the light modulation element by area division, and projecting R, G, B light projection areas A “color scroll method” that moves (scrolls) with time is often used.

  In particular, when a white light source is used as the light source, the color scroll method uses all of the R, G, and B light that has been dispersed for image display at the same time, so it is necessary from white light using a color filter such as a color wheel. Compared with the color sequential method, which extracts only different types of light, discards other types of light, and sequentially projects only R, G, B light in a time-sharing manner, it has the advantage that the light use efficiency is higher. is there.

Here, an example of a conventional projection type image display apparatus using a color scroll method will be described.
FIG. 21 is an explanatory diagram showing an example of the configuration of a projection-type image display apparatus using a conventional color scroll method.

  As shown in FIG. 21, a conventional color scroll projection-type image display apparatus 110 has an optical scanning unit 101 that performs optical scanning by rotating the rotating prism 139 using the regular prismatic rotating prism 139 as an optical path displacement element. A white light source lamp 1 having a spectrum in the visible light range, and light emitted from the white light source lamp 1 in three colors of red (R), green (G), and blue (B). The dichroic mirrors 3, 4, 5 to be separated and the separated light beams R, G, B separated and reflected by the dichroic mirrors 3, 4, 5 are diffused and shaped, and a rotating prism 139 as an optical path displacement element Diffusing shaping rods 6, 7, 8 projected onto the light, a regular quadrangular prism rotating prism 139 that receives the separated lights R, G, B emitted from the rods 6, 7, 8, and the rotating prism 139. The Rotating means (not shown), a projection lens 10 for projecting the output light of the rotating prism 139 onto the light modulation element 11, the reflecting mirrors 12, 13, the light modulation element 11, and a projection optical system 14 onto a screen (not shown). It is equipped with.

Hereinafter, the operation of the projection type image display apparatus 110 will be described.
Light emitted from the white light source lamp 1 having a spectrum in the visible light range is blue (B) by the dichroic mirror 3 through the lens 2, green (G) by the dichroic mirror 4, and red (R) by the dichroic mirror 5. Are separated into three colors of separated light R, G and B.

The three color separated lights R, G, and B separated and reflected by the dichroic mirrors 3, 4, and 5 are the light diffusion shaping rod 6 (B), rod 7 (G), and rod for each color, respectively. 7 (R). The separated lights R, G, and B emitted from the rods 6, 7, and 8 are incident on the rotating prism 139 as shown in FIG.
The incident angles of the separated lights R, G, and B from the rods 6, 7, and 8 with respect to the rotating prism 139 change as the rotating prism 139 rotates.

For this reason, the region of light for each color that has passed through the rotating prism 139 and projected onto the light modulation element 11 moves (scrolls) as the rotating prism 139 rotates.
The light modulation element 11 performs light modulation and generates an image in accordance with the type and area of the projected light. The image generated by the light modulation element 11 is projected onto a screen (not shown) through a projection optical system 14 onto the screen.

  However, in the color scroll method having the advantages as described above, by using the optical scanning means 101 that performs optical scanning by rotating the rotating prism 139 using the regular prismatic rotating prism 139 as an optical path displacement element. The following problems existed.

  That is, wind noise is likely to occur due to the relationship between the shape of the rotating prism 139 and the rotational direction of the rotating prism 139. In particular, it is effective to increase the scroll speed in order to suppress the occurrence of color breaks. However, when the rotation speed of the prism is increased, there arises a problem that wind noise increases.

  In addition, the scanning speed of the projection area of the light projected on the light modulation element 11 differs depending on the position on the light modulation element 11 such that the scanning speed is higher at both the upper and lower ends than the center of the light modulation element 11. As a result, the brightness of the screen image is lower at the upper and lower ends than in the center, and uneven brightness occurs in the image.

  Furthermore, the fluctuation of the optical path length caused by the rotation of the rotating prism 139 and the influence of wavelength dispersion depending on the incident angle of light on the rotating prism 139 cause focal vibration and enlargement of chromatic aberration, and the display image is blurred. There has been a problem that the quality of the image is deteriorated (see FIG. 11).

Here, “color break” will be described.
A display device that displays full-color images sequentially displays red, blue, and green images in a time-sharing manner, and the viewer's brain superimposes red, blue, and green image information that are displayed with a time shift. And using it as a full-color image.
And, in such a video display method, due to the movement of the viewer's line of sight, etc., if some of the red, blue and green video information cannot be acquired, or the superposition processing of the video in the brain is not successful, One of the colors red, blue, and green falls out of a portion of the image, causing a phenomenon in which the color tone of the image changes. This phenomenon is called “color break”.

  Therefore, as countermeasures for the above-described conventional problems, as shown in FIG. 22, the dichroic cube 15 from which the separated lights R, G, and B are emitted and the first focus lens into which the separated lights R, G, and B are incident. 16, a scanning element 17 that scans the separated lights R, G, and B that have passed through the first focus lens 16, and a post-focus lens 20 that receives the separated lights R, G, and B scanned by the scanning element 17. The scanning element 17 is composed of two cylindrical lens arrays 18 and 19 which are arranged so that the arrangement interval is equal to the focal length and swings positively and negatively, and serves as an optical scanning unit instead of the rotating prism 139. An optical system to be used has been proposed (see Patent Document 1).

According to such a scroll optical system, since the rotating prism is not used as the optical scanning means, the fluctuation of the optical path length caused by the rotation of the prism, the focus vibration caused by the wavelength dispersion depending on the incident angle of the light to the prism, The expansion of chromatic aberration can be improved.
Special Table 2002-541512A

  However, like the optical system described in Patent Document 1, in order to scroll the projection area of the light on the light modulation element 11, it is composed of two cylindrical lens arrays 18 and 19 that swing positively and negatively. In the method using the scanning element 17, it is difficult to swing the cylindrical lens arrays 18 and 19 positively and negatively so as to accurately scan all the light beam heights of the input pattern. In addition, there is a problem that the driving mechanism for moving the cylindrical lens arrays 18 and 19 positively and negatively is required, so that the mechanism is complicated.

  The present invention has been made in view of the above-described conventional problems, and reduces noise during operation of the apparatus with a simple configuration, reduces brightness unevenness of a projected image, and suppresses focal vibration to reduce the image quality. An object of the present invention is to provide an optical path displacing element, an optical scanning unit, and a projection type image display device with improved quality.

  The present invention relates to an optical path displacing element, in which separated light emitted from a light source and separated for each of a plurality of specific wavelength band components is incident and transmitted or reflected, and the emission position of the incident separated light in the optical path is displaced. The optical path displacing element, the optical path displacing element is constituted by a prism body in which the separation light incident surface and the exit surface are spirally and endlessly formed, and by displacing the prism body, The path of the separated light incident on the prism body is displaced.

  In the prism body, the cross-sectional shape in a direction substantially perpendicular to the displacement direction is a regular polygonal shape, and the cross-sectional shape at an arbitrary position is a similar shape, and n / 2πrad (n is a natural number where n ≧ 1). One end side and the other end side of each of a ridge formed by twisting and formed by an adjacent entrance surface or exit surface of the prism body and a center line along the displacement direction of the prism body Are preferably formed in an endless manner.

The prism body is formed in an annular shape, and includes a Z-axis as a rotation axis of the prism body when the prism body is rotationally displaced about the center of the annular shape, and includes a reference circle having a radius r (r> 0) when the prism body is rotated. The plane perpendicular to the Z axis is the XY plane, the intersection of the XY plane and the Z axis is the reference point O: (x, y, z) = (0, 0, 0), one point A on the reference circle, the reference The angle ∠AOB formed by the point O, the intersection B of the X axis and the reference circle B = (r, 0, 0) is θ, and the coordinate of one point A on the reference circle is A (θ) = (r · cos (θ) , R · sin (θ), 0), an intersection of a plane including A (θ) with one side of the Z-axis being the edge of m points (m ≧ 3 is a natural number) of the prism body and Pk (θ) = ( xk (θ), yk (θ), zk (θ)) (k is a natural number of 1 ≦ k ≦ m), Pk (θ), A, and the angle formed by the reference point O are ζk (θ), ζ1 (θ ) Θ = The initial phase when the δ (0 ≦ | δ | <2π), when the length of one side of the prisms defining R (theta), and the coordinates of Pk (theta) is,
zk (θ) = (R (θ) / √2) · sin (ζk (θ))
xk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · sin (θ)
It is preferable that the relational expression is satisfied.

Furthermore, the prism body is
R (θ) = R1 (r> R1 / √2> 0)
ζk (θ) = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
It is preferable that the relational expression is satisfied.

Furthermore, the prism body is
R (θ) is
R (θ) = R1 (r√2>R1> 0)
ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
f (θk1) is
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
It is preferable that the relational expression is satisfied.

The prism body is
ζk (θ) is
ζk (θ) = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
It is preferable that the relational expression is satisfied.
Here, MOD (b, c) is a function that returns a remainder when b is divided by c.

Furthermore, the prism body is
ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
f (θk1) is
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
It is preferable that the relational expression is satisfied.

  In addition, the present invention relates to an optical scanning unit, and injects and transmits or reflects the separated light emitted from the light source and separated for each of the plurality of specific wavelength band components, and sets the emission position of the optical path of the incident separated light. An optical path displacing element for displacing and an optical path displacing element displacing means for displacing the optical path displacing element, and irradiating the optical path displacing element by controlling the emission position of the light incident on the optical path displacing element. In the optical scanning means configured to do so, the optical path displacing element is constituted by a prism body in which the portions that become the incident surface and the exit surface of the separated light are spirally and endlessly formed, and the optical path displacing element displacing unit includes: Further, the path of the plurality of separated lights incident on the prism body is temporally displaced by rotationally displacing the prism body constituting the optical path displacement element.

  As the optical path displacement element, it is preferable to use the optical path displacement element described in the invention related to the optical path displacement element described above.

  Further, the optical path displacement element is provided to be rotatable on a virtual plane substantially perpendicular to the optical path on which the separated light is incident, and the prism body is displaced by the rotation of the optical path displacement element, so that the prism body is displaced. The path of the incident separated light is preferably displaced at a constant speed.

  The present invention also relates to a projection-type image display apparatus, comprising: a light separating unit that separates light emitted from a light source into a plurality of specific wavelength band components; and a separated light separated for each color by the light separating unit. A light modulation element that modulates each color to form an image, a projection unit that projects an image formed by the light modulation element, and a light scanning unit disposed between the light separation unit and the light modulation element. In the projection type image display apparatus, the optical scanning means includes an optical path displacement element formed by a prism body in which the portions to be the incident surface and the exit surface of the separated light are spirally and endlessly formed, and the optical path displacement An optical path displacing element displacing unit that rotationally displaces the prism body constituting the element is provided, and the paths of the plurality of separated lights incident on the prism body are temporally displaced.

  As the optical scanning unit, it is preferable to use the optical scanning unit described in the invention related to the optical scanning unit described above.

  In addition, the light separation means irradiates the light of each of the three primary colors individually or simultaneously with a plurality of selective wavelength band transmission / reflection mechanisms for separating the light emitted from the light source into the three primary colors of R, G, and B. It is preferable to provide a mixing mechanism that makes the distribution uniform.

  Furthermore, it is preferable that the mixing mechanism includes at least a pair of fly-eye lenses that uniformly or simultaneously illuminate each of the three primary colors R, G, and B.

  According to the present invention, an optical path displacing element and an optical scanning unit that reduce noise during operation of the apparatus with a simple configuration, reduce luminance unevenness of a projected image, and improve the image quality by suppressing focus vibration. And a projection type image display apparatus can be provided.

  That is, according to the present invention, the optical path displacing element is constituted by a prism body in which the portions that become the incident surface and the exit surface of the separated light are formed in a spiral and endless shape, and the prism body is rotated to form the prism body. By displacing the path of the incident separated light, the air resistance can be made smaller than the conventional rotating prism and the wind noise can be reduced as compared with the conventional rotating prism system.

  Further, the prism body is formed so that the cross-sectional shape in a direction substantially perpendicular to the displacement direction is a regular polygonal shape, and the cross-sectional shape at an arbitrary position is a similar shape, and n / 2π rad (n is a natural number where n ≧ 1) ) One end side and the other end side of each of the ridge formed by twisting and formed by the adjacent entrance surface or exit surface of the prism body and the center line along the displacement direction of the prism body , The prism body is rotated about the endless center as a central axis, and the path of the separated light incident on the prism body can be displaced. Thereby, compared with the conventional rotating prism system, air resistance can be made smaller than that of the conventional rotating prism, and wind noise can be reduced.

Further, the prism body is formed in an annular shape, and the rotational axis of the prism body when rotationally displaced with the annular center as a central axis is the Z axis, and the prism body includes a reference circle having a radius r (r> 0) when rotated. The plane perpendicular to the axis is the XY plane, the intersection of the XY plane and the Z axis is the reference point O: (x, y, z) = (0, 0, 0), one point A on the reference circle, the reference point An angle ∠AOB formed by an intersection B = (r, 0, 0) between the O and X axes and the reference circle is θ, and a coordinate of one point A on the reference circle is A (θ) = (r · cos (θ), r · sin (θ), 0), an intersection of a plane including m (the natural number of m ≧ 3) ridges of the prism body and the A (θ) with the Z axis as one side is Pk (θ) = (xk (Θ), yk (θ), zk (θ)) (k is a natural number of 1 ≦ k ≦ m), Pk (θ), A, and the angle formed by the reference point O are ζk (θ), ζ1 (θ) Θ = 0 The initial phase when δ (0 ≦ | δ | <2π), when the length of one side of the prisms defining R (theta), and the coordinates of Pk (theta) is,
zk (θ) = (R (θ) / √2) · sin (ζk (θ))
xk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · sin (θ)
By satisfying this relational expression, it is possible to realize a simple optical path displacement element with low air resistance during rotation and a structure that reduces the difference in optical scanning speed depending on the position on the projection surface, and the brightness of the light projection surface Unevenness can be improved.

Furthermore, the prism body is
R (θ) is
R (θ) = R1 (r> R1 / √2> 0)
ζk (θ) is
ζk (θ) = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
By satisfying this relational expression, it is possible to reduce the difference in the optical scanning speed depending on the position on the projection surface and improve the luminance unevenness of the light projection surface.

Also, the prism body is
R (θ) is
R (θ) = R1 (r√2>R1> 0)
ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
f (θk1) is
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
By satisfying this relational expression, fluctuations in the path length due to the optical path displacement element can be suppressed, and blurring of the image due to the influence of focal vibration can be improved.

Furthermore, the prism body is
ζk (θ) is
ζk (θ) = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
By satisfying this relational expression, it is possible to improve the influence of uneven brightness on the light projection surface and focus vibration.

Furthermore, the prism body is
ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
f (θk1) is
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
By satisfying this relational expression, it is possible to improve the influence of uneven brightness on the light projection surface and focus vibration.

  According to the present invention, in the optical scanning means for performing optical scanning by displacing the optical path displacement element and controlling the emission position of the light incident on the optical path displacement element, the optical path displacement element is made incident on the separated light. A portion that becomes a surface and an emission surface is formed of a spiral and endless prism body, and the optical path displacing element displacing means is configured to rotate a plurality of the prism bodies so that a plurality of light beams are incident on the prism body. Since the path of the separated light is temporally displaced, the air resistance is smaller than that of the conventional rotating prism and the wind noise can be reduced as compared with the conventional rotating prism system.

  Further, by using the above-described optical path displacement element as the optical path displacement element, wind noise generated by rotation of the prism body of the optical scanning unit that performs optical scanning by rotating the prism body, and light that varies depending on the position on the optical scanning surface The image blurring due to the scanning speed and the focus vibration can be improved.

  Further, the optical path displacement element is provided so as to be rotatable on a virtual plane substantially perpendicular to the optical path on which the separated light is incident, and the prism body is displaced in accordance with the rotation of the optical path displacement element. The path of the separated light incident on the body can be displaced at a constant speed, the fluctuation of the path length can be suppressed, and the blurring of the image due to the influence of the focus vibration can be improved.

  The present invention also provides a light separating means for separating light emitted from a light source into a plurality of specific wavelength band components, and forming an image by modulating the separated light separated for each color by the light separating means for each color. A projection-type image display device comprising: a light modulation element that performs projection; a projection unit that projects an image formed by the light modulation element; and a light scanning unit that is disposed between the light separation unit and the light modulation element. The optical scanning unit rotates an optical path displacing element formed by a prism body in which a portion to be an incident surface and an output surface of separated light is formed in a spiral shape and an endless shape, and the prism body constituting the optical path displacing element. An optical path displacing element displacing means for displacing, and by temporally displacing the paths of a plurality of separated lights incident on the prism body, the air resistance is higher than that of the conventional rotating prism system compared to the conventional rotating prism system. Small, winded It is possible to reduce the size.

  Further, as the optical scanning unit, an optical path displacement element formed by a prism body in which the portions to be the incident surface and the exit surface of the separated light are spirally and endlessly formed, and the prism body constituting the optical path displacement element The optical path displacing element displacing means for temporally displacing the paths of the plurality of separated lights incident on the prism body by rotationally displacing the prism body, compared with the conventional rotating prism system, The air resistance is smaller than that of the prism, and wind noise can be reduced.

  Furthermore, the light separation means irradiates light of each of the three primary colors individually or simultaneously with a plurality of selective wavelength band transmission / reflection mechanisms for separating the light emitted from the light source into the three primary colors of R, G, and B. By providing a mixing mechanism that makes the distribution uniform, fluctuations in the scanning speed on the light modulation element can be reduced, fluctuations in the optical path length due to optical path displacement can be reduced, and focus vibration can be reduced.

  Furthermore, as the mixing mechanism, at least a pair of fly-eye lenses that uniformly or simultaneously uniformly illuminate each of the three primary colors R, G, and B can be provided, so that fluctuations in scanning speed on the light modulation element can be reduced. It is possible to reduce the fluctuation of the optical path length due to the displacement and reduce the focus vibration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is an explanatory diagram showing a configuration of a projection type image display apparatus employing an optical path displacement element according to Embodiment 1 of the present invention, and FIG. 2 is an explanatory diagram showing a configuration of the optical path displacement element according to Embodiment 1 of the present invention. FIG. 3 is a partial detail view showing the positional relationship between the optical path displacement element and a rod that emits separated light to the optical path displacement element, and FIG. 4A is an explanation showing the optical path of the separated light passing through the optical path displacement element. FIG. 5B is an explanatory view showing another example of the cross-sectional shape, and FIG. 5 is an explanatory view showing the incident direction of the separated light to the optical path displacement element.

  As shown in FIG. 1, the projection-type image display apparatus 100 according to the first embodiment rotates the annular prism 9 along the circumferential direction using an endless annular prism 9 as an optical path displacement element. The optical scanning means 101 for performing optical scanning is provided, and the white light source lamp 1 having a spectrum in the visible light region, the lens 2, and the light emitted from the white light source lamp 1 are red (R) and green. (G), dichroic mirrors 3, 4 and 5 that separate into three colors of blue (B) and the dichroic mirrors 3, 4, and 5 and the reflected three-color separated light R, G, and B are diffused Diffusion shaping rods 6, 7, 8 that are shaped and projected onto an annular prism 9 as an optical path displacement element, and an annular prism that receives the separated lights R, G, B emitted from the rods 6, 7, 8 9 and rotating means 9c for rotating the annular prism 9 , And includes a projection lens 10 for projecting the light emitted annular prism 9 to the light modulation device 11, the reflecting mirror 12, the light modulation element 11, and a projection optical system 14 to the screen.

  As shown in FIGS. 2, 3, and 4, the annular prism 9 as the optical path displacement element according to the first embodiment is separated light that is emitted from the white light source lamp 1 and separated for each of a plurality of specific wavelength band components. R, G, and B are incident and transmitted or reflected, and the exit position of the optical path of the incident separated light is displaced. The cross-sectional shape is an endless shape with a regular quadrangle, and the incident surface of the separated light In addition, the surface to be the emission surface is formed in a spiral shape.

  As shown in FIG. 2, the annular prism 9 is obtained by twisting a prism column 9a formed in a columnar shape having the same shape at one end 9a1 and the other end 9a2 by n / 2π rad (n = 1), that is, 90 °. It is bent in a state, and the center line 9b of the prism column 9a is connected endlessly, and the respective edges of the one end 9a1 and the other end 9a2 are connected to form a continuous annular shape.

Here, the position coordinates in the annular prism 9 will be described with reference to the drawings.
However, in FIG. 7, a prism column described later is bent in a state of being twisted by 180 ° to be formed into a continuous annular shape. Accordingly, in this embodiment, only the positional relationship is referred to.

  As shown in FIG. 7, the position coordinates in the annular prism 9 are drawn when the annular prism 9 is rotated, with the axis of rotation passing through the center of the annular inner circle as the rotational axis and the rotational axis as the Z axis 9 z. A plane including a circle (reference circle) with a radius r (r> 0) is an XY plane, an intersection of the XY plane and the Z axis 9z is (x, y, z), and a reference point O is (0, 0, 0). To do.

  One point on the reference circle of the annular prism 9 is A, the intersection point of the X axis and the reference circle is B, the intersection point B is (r, 0, 0), and further, one point A, a reference point O, The angle ∠AOB formed by the intersection point B is θ, and the coordinates A (θ) of the point A are (r · cos (θ), r · sin (θ), 0).

Further, the coordinates Pk (θ) of the intersection Pk of the plane including the four edges of the annular prism 9 and the coordinate A (θ) with the Z axis 9z as one side are expressed as (xk (θ), yk (θ), zk). (Θ)).
Here, k is a natural number of 1 ≦ k ≦ 4.

And
The angle formed by the intersection point Pk (θ), one point A, and the reference point O is ζk (θ), and δ is the initial phase ζ1 (0) when θ = 0, and is defined as 0 ≦ | δ | <2π. It is a thing.

  As shown in FIG. 3, the rods 6, 7, and 8 are arranged in a direction along the rotation axis of the annular prism 9, and the rods 6, 7, and 8 are arranged in parallel to each other. So that the annular prism 9 always faces the annular prism 9 even if the annular prism 9 rotates.

  As shown in FIG. 4, the separated lights R, G, and B emitted from the rods 6, 7, and 8 are emitted from the annular prism 9 with the optical path displaced when passing through the annular prism 9. .

  Here, the positional relationship between the annular prism 9 and the separated light when the separated light is incident on the annular prism 9 will be described.

  Since the annular prism 9 is formed in a continuous annular shape in a state where it is twisted by 90 °, the separated light emitted to a predetermined position of the annular prism 9 by the rods 6, 7, 8 is shown in FIG. Thus, when the annular prism 9 rotates along the tangential direction (circumferential direction) of the reference circle, the incident position on the annular prism 9 is displaced with time (in the direction of the arrow in the figure), When the ring prism 9 rotates once, it enters at a position twisted by 90 °.

  That is, the incident angle of the separated light can be changed by 90 ° by rotating the annular prism 9 once.

Next, the operation of the projection type image display apparatus 100 of the present embodiment will be described with reference to the drawings.
First, the emitted light from the white light source lamp 1 having a spectrum in the visible light region is blue (B) by the dichroic mirror 3 and green (G) by the dichroic mirror 4 via the lens 2 as shown in FIG. The dichroic mirror 5 separates red (R) and three colors of R, G, and B.

  The R, G, and B light beams separated and reflected by the dichroic mirrors 3, 4, and 5 are respectively, for each color, a light diffusion shaping rod 6 (for B), a rod 7 (for G), And it injects into the rod 7 (for R). The separated lights R, G, and B emitted from the rods 6, 7, and 8 are incident on the annular prism 9, as shown in FIGS.

  The incident angles of the separated lights R, G and B emitted from the rods 6, 7 and 8 with respect to the prism surface of the annular prism 9 change as the annular prism 9 rotates as shown in FIG. 5.

  For this reason, when the light that has passed through the annular prism 9 is projected onto the light modulation element 11, the region of the light for each color projected onto the light modulation element 11 is the same as when the rotating prism is used. As the annular prism 9 rotates, it moves (scrolls).

  The light modulation element 11 performs light modulation according to the type of projected light and its region, and generates an image. The image generated by the light modulation element 11 is projected onto a screen (not shown) through a projection optical system 14 onto the screen.

  Since it is configured as described above, according to the color scroll projection-type image display apparatus 100 according to the first embodiment, a circular surface in which the incident surfaces and the exit surfaces of the separated light R, G, B are formed in a spiral shape. By adopting an optical path scanning means including an annular prism 9 and rotating the annular prism 9 along the tangential direction (circumferential direction) of the reference circle, the separated lights R and G incident on the annular prism 9 are obtained. , B can be changed.

  Further, there is a problem of optical scanning means for performing optical scanning by rotating the regular prism as a conventional optical path displacement element by rotating the annular prism 9 along the tangential direction (circumferential direction) of the reference circle. In other words, it is possible to reduce the generation of air resistance and wind noise caused by the rotation of the prism.

  That is, according to the annular prism 9 of the first embodiment, the incident surface and the exit surface of the separated light R, G, B in the annular prism 9 are spiral along the displacement direction (rotation direction), that is, the circumferential direction. Since it is twisted and tilted, by rotating the annular prism 9 in the tangential direction (circumferential direction) of the reference circle, the air received at the entrance surface and the exit surface is not inclined at right angles. Therefore, air resistance and wind noise when the annular prism 9 rotates can be suppressed.

  In the first embodiment, the circular prism 9 having a square cross section is used as the optical path displacement element. However, the present invention is not limited to this, and for example, (b) in FIG. ), An annular prism 90 having a regular hexagonal cross section may be used.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described in detail with reference to the drawings.
6 is a perspective view showing a configuration of an annular prism according to Embodiment 2 of the present invention, FIG. 7 is an explanatory diagram showing position coordinates of the annular prism, and FIG. 8 is an explanation indicating an arbitrary cross section of the annular prism. 9, (a), (b), and (c) are explanatory diagrams showing arbitrary instructed cross-sectional shapes of the annular prism, and (a), (b), and (c) in FIG. FIG. 9 is an explanatory diagram showing an optical path of separated light at an arbitrary position of the annular prism in 9 (a), (b), and (c).

  The second embodiment employs an annular prism 109 twisted by 180 ° as shown in FIG. 6 in place of the annular prism 9 as an optical path displacement element in the projection type image display apparatus 100 according to the first embodiment. .

The configuration of the projection-type image display device (not shown) in the second embodiment is the same as that of the projection-type image display device 100 according to the first embodiment except for the annular prism 109. Description is omitted, and only the configuration of the annular prism 109 will be described.
The same components as those of the projection type image display apparatus 100 of the first embodiment are used for the description of the second embodiment by using the same reference numerals.

  As shown in FIG. 6, the annular prism 109 as the optical path displacement element according to the second embodiment receives separated light (not shown) emitted from the white light source lamp and separated for each of the plurality of specific wavelength band components. Are transmitted or reflected, and the exit position of the optical path of the incident separated light is displaced, and the cross-sectional shape is an endless shape with a regular quadrangle, and the surfaces that become the incident and exit surfaces of the separated light are spiraled. It is formed in a shape.

  The circular prism 109 is formed by bending a prism column formed in a column shape having the same shape and dimension of the one end portion 109a1 and the other end portion 109a2 in a state of being twisted by nπrad (n = 2), that is, 180 °. The center lines are connected in an endless manner, and the respective edges of the one end 109a1 and the other end 109a2 are connected to form a continuous annular shape.

Here, the position coordinates in the annular prism 109 will be described with reference to the drawings.
As in the first embodiment, the position coordinates in the annular prism 109 are set such that the axis of rotation passing through the center of the inner circular portion of the annular shape is the rotational axis, as shown in FIG. A plane including a reference circle having a radius r (r> 0) drawn when the prism 109 is rotated is an XY plane, and an intersection of the XY plane and the Z axis 109z is (x, y, z), and a reference point O is (0, 0). , 0).

  A point on the reference circle of the annular prism 109 is A, an intersection point of the X axis and the reference circle is B, and the intersection point B is (r, 0, 0), and further, one point A, a reference point O, and an intersection point B An angle ∠AOB formed by ω is θ, and a coordinate A (θ) of a point A on the reference circle is (r · cos (θ), r · sin (θ), 0).

Further, the intersection Pk (θ) of the plane including the four edges of the twisted annular prism 109 and the A (θ) with the Z axis 109z as one side is represented by (xk (θ), yk (θ), zk (θ) ).
Here, k is a natural number of 1 ≦ k ≦ 4.

  The angle formed by the Pk (θ), A, and the reference point O is defined as ζk (θ), and δ is defined as 0 ≦ | δ | <2π in the initial phase ζ1 (0) when θ = 0. Formed.

The coordinates (xk (θ), yk (θ), zk (θ)) of the Pk (θ) are
zk (θ) = (R (θ) / √2) · sin (ζk (θ))
xk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · sin (θ)
And

The R (θ) and ζk (θ) are
R (θ) = R1 (r> R1 / √2> 0)
ζk (θ) = MOD ((1/2) · θ + δ + (k−1) · π / 2, 2π)
The relational expression of
Here, MOD (b, c) is a function that returns a remainder when b is divided by c.

  Further, as shown in FIG. 8, the circular prism 109 has a cross-sectional shape at arbitrary positions a, b, and c in the circular prism 109 having a change Δθ of the rotation angle θ and a change Δζk (θ) of the ζk (θ). Twist is formed so that a proportional relationship is generated between the two.

  As shown in FIGS. 1 and 3, rods 6, 7, and 8 are arranged on the annular prism 109 in the direction along the rotation axis of the annular prism 109 and parallel to each other, as in the first embodiment. Are arranged close to the annular prism 109 so that the annular prism 109 always faces the annular prism 109 even when the annular prism 109 rotates.

  Next, the positional relationship between the annular prism 109 and the separated light when the separated light is incident on the annular prism 109 will be described.

  Since the annular prism 109 is formed in a continuous annular shape in a state of being twisted by 180 °, the separated light emitted to the predetermined position of the annular prism 109 by the rods 6, 7, and 8 is as shown in FIG. Further, when the annular prism 109 rotates along the tangential direction (circumferential direction) of the reference circle, the incident position on the annular prism 109 is displaced with time (in the direction of the arrow in the drawing), When the ring prism 109 rotates once, it enters at a position twisted 180 °.

  That is, the incident angle of the separated light can be changed by 180 ° by rotating the annular prism 109 once.

Next, the incident angle of the separated light with respect to the annular prism 109 will be described with reference to the drawings.
First, as shown in FIG. 1, the emitted light from the white light source lamp 1 having a spectrum in the visible light region is blue (B) by the dichroic mirror 3 and green (G) by the dichroic mirror 4 as in the first embodiment. The dichroic mirror 5 separates red (R) and R, G, B colors.

  The R, G, and B light beams separated and reflected by the dichroic mirrors 3, 4, and 5 are respectively, for each color, a light diffusion shaping rod 6 (for B), a rod 7 (for G), And it injects into the rod 7 (for R). The R, G, and B outgoing lights from the rods 6, 7, and 8 are incident on the annular prism 109 as shown in FIGS.

  The incident angles of the three color separated lights R, G, and B incident on the prism surface of the annular prism 109 are, for example, as shown in FIGS. 9A, 9B, and 9C. It changes in accordance with the incident position that changes relatively with the rotation of the prism 109.

  As a result, the output light from the annular prism 109 is separated as shown in FIGS. 10A, 10B, and 10C in the same manner as when a conventional rotating prism is used. The optical path gradually changes to perform optical scanning (scrolling operation).

  Since it is configured as described above, according to the second embodiment, the annular prism 109 is formed in a continuous annular shape in a state of being twisted by 180 °, so that the annular prism 109 is rotated in the tangential direction of the reference circle. By doing so, the air received at the entrance surface and the exit surface strikes diagonally without hitting at right angles, so that air resistance and wind noise can be suppressed.

  Further, by increasing the torsional magnitude (n) of the annular prism 109, the scrolling speed can be increased without increasing the rotational speed of the annular prism 109.

  Further, the circular prism 109 is formed by twisting the cross-sectional shape at an arbitrary position so that a proportional relationship is generated between the change Δθ of the rotation angle θ and the change Δζk (θ) of the rotation angle θ. Because the cross-sectional shape in the almost vertical direction is a regular polygon and the cross-sectional shape at an arbitrary position is made similar, the light scanning speed that varies depending on the position on the optical scanning surface and the blurring of the projected image due to focus vibration are improved. can do.

(Embodiment 3)
Next, Embodiment 3 of the present invention will be described in detail with reference to the drawings.
In the third embodiment, as shown in FIG. 6, an annular prism 209 twisted by 180 ° is used instead of the annular prism 9 as the optical path displacement element in the projection type image display apparatus 100 according to the first embodiment, as in the second embodiment. Adopted.

As shown in FIGS. 6 and 7, the annular prism 209 is replaced with the circular prism 109 of the second embodiment described above, and the coordinates (xk (θ), yk) of Pk (θ) in the annular prism 109 are used. (Θ), zk (θ)),
zk (θ) = (R1 / √2) · sin (ζk (θ))
xk (θ) = {r + (R1 / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R1 / √2) · cos (ζk (θ))} · sin (θ)
It is what.

The ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((1/2) · θ + δ + (k−1) · π / 2, 2π)
f (θk1)
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
The relational expression of
Here, ASIN (a) is a function that returns the sign of the numerical value of a, f (a) = 1 (a ≧ 0), f (a) = − 1 (θk1 <0).

  The relationship between the rotation angle θ (θ1 or θ2) of the annular prism 209 and the coordinates (x, y, z) of P1 (θ) is as shown in (a), (b), and (c) of FIG. The corners PL1, PL2 and PL3 of the regular square cross section at an arbitrary position are contours of the regular square cross section at a position where the incident angle of light is 0 ° (the separated light is incident perpendicularly to the incident surface). It is formed so that it may become a position along.

  Regarding the positional relationship between the annular prism 209 and the separated light when the separated light is incident on the annular prism 209 and the incident angle of the separated light with respect to the annular prism 209, the separated light is incident on the annular prism 209. Since the operation is the same as in the second embodiment described above, the description thereof is omitted.

Next, a state in which the separated light is incident on the annular prism 209 and the output is projected on the light modulation element will be described.
As shown in FIG. 3, when separating light is projected onto the annular prism 209, the annular prism 209 is rotated at a constant speed in the tangential direction of the reference circle, and the output is projected onto the light modulation element 11, As shown in FIG. 11, when the incident angle of the separated light on the annular prism 209 changes, the imaging position f on the light modulation element 11 is displaced.

  FIG. 12 shows changes in the moving speed of the irradiation area on the light modulation element 11 when the annular prism 209 is rotated. According to this, it can be seen that according to the annular prism 209, the fluctuation of the scanning speed due to the position on the light modulation element 11 is small.

  Since it is configured as described above, according to the third embodiment, the annular prism 209 is formed in a continuous annular shape in a state where the annular prism 209 is twisted by 180 °, as in the second embodiment. By rotating in the tangential direction of the circle, the air received at the entrance surface and the exit surface strikes diagonally without hitting the right angle direction, so that air resistance and wind noise can be suppressed.

  In addition, the circular prism 209 is twisted so that the cross-sectional shape at an arbitrary position is proportional to the change Δθ of the rotation angle θ and the change Δζk (θ) of the ζk (θ) as in the second embodiment. Since the cross-sectional shape in the direction substantially perpendicular to the displacement direction is a regular polygonal shape and the cross-sectional shape at an arbitrary position is a similar shape, the scanning speed of light that differs depending on the position on the optical scanning surface, and projection by focus vibration The blur of the image can be improved.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described with reference to the drawings.
In the fourth embodiment, as in the third embodiment, as shown in FIG. 6, an annular prism 309 twisted by 180 ° is used instead of the annular prism 9 as an optical path displacement element in the projection type image display apparatus 100 according to the first embodiment. Is adopted.

As shown in FIGS. 6 and 7, the annular prism 309 is replaced with the circular prism 109 of the third embodiment described above, and the coordinates (xk (θ), yk) of Pk (θ) in the annular prism 109 are used. (Θ), zk (θ)),
zk (θ) = (R (θ) / √2) · sin (ζk (θ))
xk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · sin (θ)
Ζk (θ) as
ζk (θ) = MOD ((1/2) · θ + δ + (k−1) · π / 2, 2π)
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
It is assumed that the following functional expression is satisfied.
Here, MOD (b, c) is a function that returns a remainder when b is divided by c.

  Regarding the positional relationship between the annular prism 309 and the separated light when the separated light is incident on the annular prism 309 and the incident angle of the separated light with respect to the annular prism 309, the separated light is incident on the annular prism 309. Since the operation is the same as in the second embodiment described above, the description thereof is omitted.

  As shown in FIGS. 9A, 9B, and 9C, the relationship between the rotation angle θ of the annular prism 309 and the cross section R (θ) corresponds to the change in the rotation angle θ. The cross-sectional shape dimensions of the

  With the configuration as described above, according to the circular prism 309 of the fourth embodiment, as shown in FIG. 11, the variation in the optical path length due to the optical path displacement can be reduced, and thus the focal vibration on the light modulation element 11 is reduced. can do.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 6, the annular prism 409 of the fifth embodiment is configured by combining the configuration of the annular prism 209 of the third embodiment and the configuration of the annular prism 309 of the fourth embodiment. , The coordinates (xk (θ), yk (θ), zk (θ)) of Pk (θ) in the annular prism 409 are
zk (θ) = (R (θ) / √2) · sin (ζk (θ))
xk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · sin (θ)
As
ζk (θ)
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((1/2) · θ + δ + (k−1) · π / 2, 2π)
f (θk1)
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
It is assumed that the following functional expression is satisfied.
Here, ASIN (a) is a function that returns the sign of the numerical value of a, f (a) = 1 (a ≧ 0), f (a) = − 1 (θk1 <0).

The R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
The relational expression of
Here, MOD (b, c) is a function that returns a remainder when b is divided by c.

  The relationship between the rotation angle θ of the annular prism 409 and the coordinates (x, y, z) of P1 (θ) is shown in FIG. 7 as in the above-described embodiment. As for the relationship of θ, as shown in FIGS. 9A, 9B, and 9C, the sectional shape dimension of the annular prism 409 changes according to the change of the rotation angle θ.

  As shown in FIGS. 13A, 13 </ b> B, and 13 </ b> C, the condensing state by the annular prism 409 varies as the incident position of the annular prism 409 changes. Comparing (a) and (c) of FIG. 13, it can be seen that almost no focal vibration appears even when the optical path displacement element is rotated.

  Since it is configured as described above, according to the annular prism 409 of the fifth embodiment, the light of R, G, B is supplied to the annular prism 409 as shown in FIGS. 10 (a), 10 (b), and 10 (c). When projecting, rotating the annular prism 409 at a constant speed in the tangential direction of the reference circle, and projecting the output onto the light modulation element, the fluctuation of the scanning speed due to the position on the light modulation element as shown in FIG. As shown in FIG. 11, the fluctuation of the optical path length accompanying the optical path displacement can be reduced, and the focus vibration can be reduced.

  As shown in FIG. 14 as a modification, such an effect is obtained by separating the separated light beams R, G, B on the exit surface side of one rod 509 that projects the separated light beams R, G, B onto the optical path displacement element. This can also be confirmed in the projection type image display apparatus 500 in which dichroic filters 503, 504, and 505 corresponding to the above are arranged. At this time, light reuse is performed between the dichroic filters 503, 504, and 505 and the lamp reflector.

  Furthermore, as another modified example, as shown in FIG. 15, the projection type image display in which the fly-eye lens 620 and the reflection angles of the dichroic mirrors 3, 4, and 5 corresponding to the separated lights R, G, and B are arranged to be different from each other. It was confirmed that the same effect as in the fifth embodiment described above can be obtained in the apparatus 600.

  In the fifth embodiment, the case where the amount of twist of the annular prism 409 is n = 2 has been described, but the amount of twist n of the annular prism 409 may be arbitrarily increased or decreased as necessary. .

  In the above-described embodiment of the present invention, the transmission-type twisted annular prism has been described as the optical path displacement element. However, the optical path displacement element according to the present invention is not limited to this, for example, a modified example As shown in FIG. 16, a reflection surface 709a having a V-shaped cross section that is inclined by 45 ° with respect to the incident direction and is reflected, and the shape of the reflection surface 709a is the transmission-type twisted annular prism described above. Similarly, a reflection type optical path displacement element 709 that changes according to the angle θ may be used.

  As another modified example, as shown in FIG. 17, a reflective surface 809a having a W-shaped cross section that reflects at an angle of 45 ° with respect to the incident direction is provided, and a virtual regular square is provided on the back side of the reflective surface 809a. A reflection type optical path displacement element 809 formed so that the shape cross section 809b changes similarly to the transmission type twisted annular prism described above may be used.

  Further, as shown in FIG. 18, an optical scanning unit 909 may be configured by combining two reflective optical path displacement elements 909a and 909b as in the above-described modification.

It is explanatory drawing which shows the structure of the projection type image display apparatus by which the optical path displacement element which concerns on Embodiment 1 of this invention was employ | adopted. It is explanatory drawing which shows the structure of the said optical path displacement element. It is a partial detail drawing which shows the positional relationship of the said optical path displacement element and the rod which radiate | emits separated light to this optical path displacement element. (A) is explanatory drawing which shows the optical path of the separated light which passes the said optical path displacement element, (b) is a partial detail drawing which shows the example of other cross-sectional shapes. It is explanatory drawing which shows the incident direction of the separated light to the said optical path displacement element. It is a perspective view which shows the structure of the annular prism which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the position coordinate of the said annular prism. It is explanatory drawing which instruct | indicates the arbitrary cross sections of the said annular prism. 8A is a cross-sectional view showing the cross-sectional shape of the part a in FIG. 8, FIG. 8B is a cross-sectional view showing the cross-sectional shape of the part b in FIG. 8, and FIG. is there. FIG. 9A is an explanatory diagram showing an optical path when the separated light of FIG. 9A is transmitted substantially perpendicularly to the incident surface and the outgoing surface, and FIG. 9B is an explanatory diagram showing the separated surface of FIG. FIG. 9C is an explanatory diagram showing an optical path when transmitting obliquely with respect to the exit surface, and FIG. 9C shows an optical path when the separated light in FIG. 9C is transmitted with an inclination of approximately 45 degrees with respect to the entrance surface and the exit surface. It is explanatory drawing shown. (A) is explanatory drawing which shows the image formation position on a light modulation element when separated light permeate | transmits substantially perpendicular | vertical with respect to the entrance plane and exit surface of the said annular prism, (b) is separated light is said annular ring. It is explanatory drawing which shows the image formation position on a light modulation element when an incident angle changes to a prism. It is a graph which shows the change of the moving speed of the irradiation area | region on the light modulation element when the said annular prism rotates. (A), (b), (c) is explanatory drawing which compared the result of the focus vibration produced when rotating a continuous spiral annular prism, and the focus vibration result in a single prism rotation system. It is explanatory drawing which shows the structure of the modification of embodiment which concerns on this invention. It is explanatory drawing which shows the structure of the other modification of embodiment which concerns on this invention. It is a detailed sectional view showing the configuration of a modified example of the optical path displacement element according to the present invention. It is a detailed sectional view showing the configuration of another modification of the optical path displacement element according to the present invention. It is explanatory drawing which shows the structure of the other modification of the optical path displacement element which concerns on this invention. It is explanatory drawing which shows the outline | summary of the projection type image display apparatus by the conventional 3 plate system. It is explanatory drawing which shows the outline | summary of the projection type image display apparatus by the conventional single plate system. It is explanatory drawing which shows an example of a structure of the projection type image display apparatus by the conventional color scroll system. It is explanatory drawing which shows the outline | summary of the projection type image display apparatus which employ | adopted the cylindrical lens array as the conventional optical scanning means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 White light source lamp 2 Lens 3, 4, 5 Dichroic mirror 6, 7, 8 Rod 9, 90, 109, 209, 309, 409 Toric prism 10 Projection lens 11 Light modulation element 12, 13 Reflection mirror 14 Projection optical system 15 Dichroic cube 16 Focus lens 100, 110, 500, 600 Projection type image display device 101 Optical scanning means 119r, 119g, 119b, 129 Light modulation element 139 Rotating prism 503, 504, 505 Dichroic filter 509 Rod 620 Fly eye lens 709 Optical path displacement Element 709a Reflective surface 809 Optical path displacement element 809a Reflective surface 809b Regular square cross section 909a, 909b Reflective optical path displacement element R, G, B Separated light

Claims (14)

An optical path displacing element that emits and transmits or reflects separated light that is emitted from a light source and separated for each of a plurality of specific wavelength band components, and that displaces the exit position of the optical path of the incident separated light,
The optical path displacing element is constituted by a prism body in which the portions that become the incident surface and the exit surface of the separated light are spirally and endlessly formed,
An optical path displacing element characterized in that the path of the separated light incident on the prism body is displaced by displacing the prism body.   In the prism body, the cross-sectional shape in a direction substantially perpendicular to the displacement direction is a regular polygonal shape, and the cross-sectional shape at an arbitrary position is a similar shape, and n / 2πrad (n is a natural number where n ≧ 1). One end side and the other end side of the ridge formed by twisting and formed by the adjacent incident surface or exit surface of the prism body and the center line along the displacement direction of the prism body, The optical path displacing element according to claim 1, wherein the optical path displacing element is formed in an endless shape. The prism body is formed in an annular shape,
The rotation axis of the prism body when rotationally displacing around the center of the ring is the Z axis,
A plane perpendicular to the Z axis including a reference circle having a radius r (r> 0) when the prism body rotates is an XY plane,
The intersection of the XY plane and the Z axis is a reference point O: (x, y, z) = (0, 0, 0),
An angle ∠AOB formed by a point A on the reference circle, a reference point O, an intersection B of the X axis and the reference circle = (r, 0, 0) is θ,
The coordinates of one point A on the reference circle are A (θ) = (r · cos (θ), r · sin (θ), 0),
An intersection of a plane including A (θ) with the edge of m places (natural number of m ≧ 3) of the prism body and the Z axis as one side is Pk (θ) = (xk (θ), yk (θ), zk (Θ)) (k is a natural number of 1 ≦ k ≦ m),
The angle formed by Pk (θ), A and the reference point O is ζk (θ),
The initial phase of ζ1 (θ) when θ = 0 is δ (0 ≦ | δ | <2π),
The length of one side of the prism body is R (θ),
When the coordinates of Pk (θ) are defined as
zk (θ) = (R (θ) / √2) · sin (ζk (θ))
xk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · cos (θ)
yk (θ) = {r + (R (θ) / √2) · cos (ζk (θ))} · sin (θ)
The optical path displacement element according to claim 1, wherein the following relational expression is satisfied. The prism body is
R (θ) is
R (θ) = R1 (r> R1 / √2> 0)
ζk (θ) is
ζk (θ) = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
The optical path displacement element according to claim 3, wherein the following relational expression is satisfied. The prism body is
R (θ) is
R (θ) = R1 (r√2>R1> 0)
ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
f (θk1) is
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
The optical path displacement element according to claim 3, wherein the following relational expression is satisfied. The prism body is
ζk (θ) is
ζk (θ) = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
The optical path displacement element according to claim 3, wherein the following relational expression is satisfied. The prism body is
ζk (θ) is
ζk (θ) = sin−1 [f (θk1)]
θk1 = MOD ((n / 4) · θ + δ + (k−1) · π / 2, 2π)
f (θk1) is
f (θk1) = ASIN (θk1) · 2 / π · MOD (θk1, π / 2)
0 ≦ MOD (θk1, 2π) <π / 2
f (θk1) = ASIN (θk1) · (1-2 / π · MOD (θk1, π / 2))
π / 2 ≦ MOD (θk1, 2π) <π
f (θk1) = ASIN (θk1) · (−2 / π) · MOD (θk1, π / 2)
π ≦ MOD (θk1, 2π) <3π / 2
f (θk1) = ASIN (θk1) · (−1 + 2 / π · MOD (θk1, π / 2))
3π / 2 ≦ MOD (θk1, 2π) <2π
R (θ) is
R (θ) = R1 / g (ζ1 (θ))
g (ζ1 (θ)) = ABS (sin (ζ1 (θ−π / 4)))
+ ABS (cos (ζ1 (θ−π / 4)))
The optical path displacement element according to claim 3, wherein the following relational expression is satisfied. An optical path displacing element that causes the separated light emitted from the light source and separated for each of the plurality of specific wavelength band components to enter and transmit or reflect, and to displace the exit position of the optical path of the incident separated light, and the optical path displacing element. An optical path displacing element displacing means for displacing the optical path displacing element, and displacing the optical path displacing element to control the emission position of the light incident on the optical path displacing element to perform optical scanning.
The optical path displacing element is constituted by a prism body in which the portions that become the incident surface and the exit surface of the separated light are spirally and endlessly formed,
The optical path displacing element displacing means temporally displaces a plurality of separated light paths incident on the prism body by rotationally displacing a prism body constituting the optical path displacing element. .   The optical scanning unit according to claim 8, wherein the optical path displacement element is the optical path displacement element according to claim 2.   The optical path displacement element is rotatably provided on a virtual plane substantially perpendicular to the optical path on which the separated light is incident, and the prism body is displaced by the rotation of the optical path displacement element, and is incident on the prism body. The optical scanning means according to claim 8 or 9, wherein the path of the separated light is displaced at a constant speed. A light separating means for separating light emitted from the light source for each of a plurality of specific wavelength band components, a light modulation element for modulating the separated light separated for each color by the light separating means for each color, and forming an image; In a projection type image display apparatus comprising: a projection unit that projects an image formed by the light modulation element; and a light scanning unit disposed between the light separation unit and the light modulation element.
The optical scanning unit rotates an optical path displacing element formed by a prism body in which a portion to be an incident surface and an output surface of separated light is formed in a spiral shape and an endless shape, and the prism body constituting the optical path displacing element. A projection-type image display device comprising: an optical path displacement element displacing means for displacing, wherein the paths of a plurality of separated lights incident on the prism body are temporally displaced.   The projection image display apparatus according to claim 11, wherein the optical scanning unit includes the optical scanning unit according to claim 8.   The light separation means includes a plurality of selective wavelength band transmission / reflection mechanisms for separating the light emitted from the light source into the three primary colors of R, G, and B, and the light irradiation distribution of the light of each of the three primary colors individually or simultaneously. The projection-type image display device according to claim 11, further comprising a mixing mechanism for performing homogenization.   14. The projection type image display device according to claim 13, wherein the mixing mechanism includes at least a pair of fly-eye lenses that uniformly or simultaneously uniformly illuminate each of the three primary colors R, G, and B.

Images