JP6299193B2 - Illumination optical system and image display device - Google Patents

Description

  The present invention relates to an illumination optical system and an image display device.

  In various scenes such as meetings and educational sites, an image display device (hereinafter referred to as “projector”) that enlarges and displays a data image output from a personal computer is used.

  Recently, projectors with a very short projection distance have become widespread. Such a projector is called an ultra short focus projector or a close range projector. The close-range projector has an advantage that the installation space can be reduced. In addition, the close range projector does not block the presenter from entering between the screen and the close range projector, so that the shadow of the presenter is not reflected on the screen.

  A general projector enlarges a lens of a projection optical system in order to enlarge an image displayed on a screen. However, when the projection distance is short, it is difficult to display a large image even if the projection lens is enlarged. Therefore, in a close-range projector, a curved reflection mirror is disposed at the end of the projection optical system instead of enlarging the lens of the projection optical system in order to cope with enlarged projection.

  The projection optical system including such a reflection mirror is installed inside the cabinet of the projector main body. In the cabinet of the projector main body, an opening is provided as a path through which light that passes through the projection lens and is reflected by the reflection mirror is projected onto the screen. If dust or dust enters the inside of the cabinet from this opening and adheres to the reflection mirror or the projection lens, the projection image is disturbed. In order to prevent these problems, a cover glass for dust prevention is installed in the cabinet opening. That is, the light projected on the screen passes through the cover glass.

  Since the close distance projector has a short distance between the screen and the projection optical system, the incident angle of light on the cover glass increases. When the incident angle to the cover glass is large, the light transmittance loss increases. In particular, the incident angle of light corresponding to the positions at both ends of the lower end on the screen is larger than the incident angle of light corresponding to other positions. That is, light corresponding to the positions at both ends of the lower end on the screen is greatly lost in the cover glass as compared with light at other positions. That is, the illuminance of the image becomes dark near both ends of the lower end of the image displayed on the screen.

  There is a method of applying a special antireflection film to the cover glass so that the transmittance loss in the cover glass can be reduced even when the incident angle to the cover glass is large. Even if such an antireflection film is applied to the cover glass, the transmittance becomes about 50% when the incident angle of light on the cover glass is around 80 degrees. In the close-range projector, the angle at which light corresponding to both ends of the lower end on the screen enters the cover glass is about 80 degrees. That is, even if a special antireflection film is applied to the cover glass, it is difficult to avoid a decrease in illuminance at the lower end of the projected image on the screen due to the cover glass.

  Further, there is known a projector that reduces the incident angle of light to the cover glass by making the cover glass into a curved shape (see, for example, Patent Document 1). However, if the cover glass is curved, the cost is increased, and the difficulty of designing the projection optical system is increased.

  Further, when the illumination optical system is made compact for the purpose of downsizing the projector, a non-telecentric illumination optical system is often used. When a non-telecentric illumination optical system is used and a reflective light valve (for example, DMD) is used for the image display element, the illumination optical system is configured while the light reflected by the reflective light valve is directed to the projection optical system. The possibility of hitting an optical component increases.

  An image displayed on the screen is formed by the light reflected by the reflective light valve. Accordingly, even if part of the light hits the illumination optical system and does not enter the projection optical system, the image on the screen is lost. Such a phenomenon is called “vignetting”. This “vignetting” causes disturbance of the display image and must be avoided.

  In order to avoid such “vignetting”, it is only necessary to cut (delete) a corresponding portion of the optical component that constitutes the illumination optical system to which the light reflected by the reflective light valve strikes. However, when a part of the optical component is cut, this reduces the illuminance of a part of the projected image. In particular, in the illumination optical system of a close-range projector having a curved reflection mirror at the end of the projection optical system, it causes a decrease in illuminance near the lower right in the projected image on the screen.

  As described above, in a conventionally known close range projector, the illuminance of the projected image is reduced due to the cover glass. Moreover, since the optical component of the illumination optical system has to be cut, the illuminance of the projected image is lowered. Due to such a decrease in illuminance, the illuminance of a part of the projected image is lowered, resulting in uneven illuminance on the screen.

  An object of the present invention is to provide an illumination optical system and an image display device including the illumination optical system that make the illuminance distribution on the screen uniform.

The present invention is an illumination optical system that is used in an image display device having a dustproof member in an optical path from a projection optical system to a projection surface and guides light emitted from a light source to a reflective light valve, The illumination optical system sequentially changes the illuminance distribution of light reflected by the rod integrator, relay lens, mirror, and light that irradiates light with uniform illuminance distribution by multiple reflection along the light traveling direction . A condenser lens, and the condenser lens is a biconvex spherical lens, and the light collected by the condenser lens has a spot diameter of φ1 at the end position of the reflective light valve. When the spot diameter of the light at the center position is φ2, the following conditional expression 1
φ1 / φ2 <1
The filled, wherein the illumination on the reflection-type light valve that will be illuminated by the illumination optical system, the most important being higher at the end position than the center position of the reflection type light valve.

  According to the present invention, the illuminance distribution on the screen can be made uniform.

1 is an optical arrangement diagram showing an embodiment of an illumination optical system according to the present invention. It is a perspective view which shows the example of the rod integrator with which the said illumination optical system is provided. It is a perspective view of the said illumination optical system. It is an example of the spot diagram when the condenser lens with which the said illumination optical system is provided is made into spherical shape. It is an example of the spot diagram when the condenser lens with which the said illumination optical system is provided is made into an aspherical shape. It is an example of illumination distribution when the condenser lens with which the said illumination optical system is provided is made into spherical shape. It is an example of illumination intensity distribution when the condenser lens with which the said illumination optical system is provided is made into an aspherical shape. 1 is an optical layout diagram showing an embodiment of an image display device according to the present invention. It is a graph which shows the example of the relationship between the incident angle to the dustproof glass with which the said image display apparatus is provided, and the transmittance | permeability.

  Hereinafter, embodiments of an illumination optical system and an image display apparatus according to the present invention will be described with reference to the drawings.

Embodiment of Illumination Optical System First, an embodiment of an illumination optical system according to the present invention will be described. FIG. 1 is an optical arrangement plan view showing an example of arrangement of optical components constituting the illumination optical system 10 according to the present embodiment.

  The illumination optical system 10 includes a lamp unit 11, a color wheel 12, a rod integrator 13, a relay lens 19, a folding mirror 16, a condenser lens 17, and a reflective light valve 18.

  The lamp unit 11 includes a lamp that is a light source, and a lamp cover that reflects light emitted from the lamp in a certain direction (direction in which the color wheel 12 is disposed).

  The color wheel 12 is disposed in the traveling direction of light from the lamp unit 11. The color wheel 12 is color conversion means for performing color conversion of light when light from the lamp unit 11 passes. The light that has passed through the color wheel 12 is incident on the rod integrator 13.

  The rod integrator 13 is disposed downstream of the color wheel 12 in the light traveling direction. The rod integrator 13 is an illuminance equalizing element that emits light with uniform illuminance of incident light.

  Here, an example of the rod integrator 13 will be described. FIG. 2 is a perspective view of the rod integrator 13. The rod integrator 13 has a hollow structure, and has a structure in which light incident from the opening is emitted from the opening on the opposite side. The wall surface (inner surface) constituting the hollow portion of the rod integrator 13 has a mirror structure. This mirror structure is constituted by a reflection mirror 131, and multi-reflects the light incident from the entrance. That is, the rod integrator 13 multi-reflects incident light to make the illuminance uniform, and then emits the light. The size of the opening of the rod integrator 13 in the present embodiment is, for example, 5.95 mm × 3.4 mm.

  Returning to FIG. The relay lens 19 includes a first relay lens 14 and a second relay lens 15. The relay lens 19 is arranged at the subsequent stage of the rod integrator 13 in the traveling direction of the light from the rod integrator 13. The relay lens 19 is a light guiding unit that guides the light emitted from the rod integrator 13 to the folding mirror 16.

  The folding mirror 16 is a means for greatly changing the traveling direction of the light so that the light from the rod integrator 13 illuminates the reflective light valve 18. The light that has traveled from the left direction in FIG. 1 to the right direction by the folding mirror 16 is folded back diagonally upward to the left.

  The condenser lens 17 is a biconvex spherical lens through which light reflected by the folding mirror 16 passes. A notch 171 is formed in a part of the condenser lens 17. The notch 171 is for preventing “vignetting” by the condenser lens 17 when the light reflected by the reflective light valve 18 is directed to the projection lens (not shown).

  The reflection type light valve 18 is an image forming element in which a plurality of micromirrors are secondarily arranged. The reflection type light valve 18 is formed by, for example, arranging square mirrors each having a side of about 10 μm so as to correspond to display pixels. If the standard of the resolution of the image to be displayed is the WXGA standard, the number of micromirrors of the reflective light valve 18 corresponding to the standard is 1280 × 800.

  The shape of each micromirror included in the reflective light valve 18 is a square. Each micromirror can form an inclination of ± 12 degrees in a diagonal direction from a two-dimensional array. The inclination of each micromirror is appropriately controlled and switched based on a video signal of an image displayed on a screen that is a projection surface.

  For example, the state where the angle of the micromirror is +12 degrees is set to the ON state, and the state where the angle of the micromirror is −12 degrees is set to the OFF state. The light illuminating the reflective light valve 18 is reflected toward the projection lens by the micro mirror in the ON state, and the light illuminating the mirror in the OFF state is in a direction different from the direction in which the projection lens is disposed. Reflected. The light reflected toward the projection lens passes through the projection lens and is projected onto the screen. On the other hand, other reflected light is absorbed by an absorbing member or the like disposed in a housing (not shown) where the illumination optical system 10 is installed.

  The tilt of each micromirror is controlled based on the video signal. The operation of the color wheel 12 that performs color conversion of illumination light is also controlled based on the video signal. By this control, an image based on the video signal is formed by the reflection type light valve 18, and this is magnified and projected on the screen.

  A protective glass 181 is disposed on the front side of the reflective light valve 18 (the side on which the reflective surface of the micromirror is disposed).

  The illumination optical system 10 can use a DMD (Digital Micromirror Device) as the reflective light valve 18. By using DMD, the illumination optical system 10 can be reduced in size.

  Here, the operation of the illumination optical system 10 will be described. The light emitted from the lamp unit 11 is condensed toward the color wheel 12 and passes therethrough. By passing through the color wheel 12, color conversion of light is performed and light of a predetermined color is obtained. The color-converted light enters the rod integrator 13. The light incident on the rod integrator 13 travels while being repeatedly reflected by the reflection mirror 131 on the inner side surface of the rod integrator 13. The light that reaches the exit end of the rod integrator 13 through multiple reflection in the rod integrator 13 becomes light with a uniform illuminance distribution. The light at the exit end of the rod integrator 13 has a uniform illuminance distribution and can be regarded as a secondary surface light source.

  The light emitted from the exit end of the rod integrator 13 passes through the relay lens 19 (the first relay lens 14 and the second relay lens 15). The light that has passed through the relay lens 19 travels to the folding mirror 16.

  The folding mirror 16 greatly changes the traveling direction of the light and folds (reflects) the light in the direction in which the reflective light valve 18 is disposed. The light reflected by the folding mirror 16 passes through the condenser lens 17. The condenser lens 17 has an effect of condensing passing light. The condenser lens 17 makes the uniform illuminance non-uniform. That is, the reflection type light valve 18 is illuminated by the light whose illuminance is nonuniform by the condenser lens 17.

  The optical axis of the illumination optical system 10 is decentered with respect to the reflective light valve 18, and the illumination intensity of the light that illuminates the reflective light valve 18 is deliberately made non-uniform. Due to the action resulting from the configuration of the illumination optical system 10, the illuminance near the lower right in the projected image on the screen becomes equivalent to the illuminance in other parts. That is, the illumination optical system 10 can make the illuminance distribution of the projected image on the screen uniform.

Next, a specific configuration of the illumination optical system 10 that exhibits the above-described action will be described. First, the specification of each optical element with which the illumination optical system 10 is provided is demonstrated. Table 1 shows specifications of the first relay lens 14, the second relay lens 15, the condenser lens 17, and the like. The focal length of the first relay lens 14 is 25.5 mm. The focal length of the second relay lens 15 is 27.1 mm. The condenser lens 17 has a biconvex spherical shape and a focal length of 38.3 mm.

Next, the amount of eccentricity of the optical axis of the illumination optical system 10 is shown in Table 2. Table 2 shows the amount of eccentricity of the optical axis of the illumination optical system 10 when the reflective light valve 18 is used as a reference.

  Here, “α rotation” and “β rotation” and x shift and y shift shown in Table 2 will be described. FIG. 3 is a perspective view of the illumination optical system 10. FIG. 3 is a view of the light emitted from the lamp unit 11 serving as a light source as viewed from the diagonally left direction in the traveling direction toward the folding mirror 16.

  The normal direction of the surface on which the minute mirror is arranged in the reflective light valve 18 is taken as the Z axis. The direction perpendicular to the Z axis and in which the lamp unit 11 is arranged is taken as the X axis. An axis perpendicular to the Z axis and the X axis is taken as a Y axis.

  The α rotation refers to rotation in the yz plane of the optical axis of the illumination optical system 10 with respect to the reflective light valve 18. In the α rotation, the counterclockwise rotation from the Z axis to the Y axis shown in FIG. 3 is defined as a positive rotation (plus rotation).

  Further, β rotation refers to rotation in the xz plane of the optical axis of the illumination optical system 10 with respect to the reflective light valve 18. In the β rotation, the counterclockwise rotation from the Z axis to the X axis direction shown in FIG. 3 is defined as a positive rotation (plus rotation).

  The x shift refers to a shift amount in the x-axis direction of the illumination optical system 10 with respect to the reflective light valve 18. The y shift is a shift amount in the y-axis direction of the illumination optical system 10 with respect to the reflective light valve 18. As shown in Table 2, the optical axis of the illumination optical system 10 is decentered with respect to the reflective light valve 18.

  In the illumination optical system 10, the distance from the center of the condenser lens 17 to the center of the reflective light valve 18 is 16.98 mm. If the distance from the center of the condenser lens 17 to the center of the reflective light valve 18 is too long, the size of the condenser lens 17 must be increased.

  If a condenser lens 17 having a large size is used, the component cost of the illumination optical system 10 increases. Therefore, the size of the condenser lens 17 is preferably as small as possible. For this purpose, the arrangement position of the condenser lens 17 needs to be close to the reflective light valve 18. However, when the condenser lens 17 is brought close to the reflective light valve 18, the light reflected by the reflective light valve 18 and directed to the projection lens (not shown) strikes the condenser lens 17. As described above, “vignetting” in which the progress of light is obstructed by the optical component reduces the light use efficiency. When the light use efficiency decreases, unevenness in brightness (illuminance unevenness) occurs in the image displayed on the screen by this light.

  Therefore, the illumination optical system 10 reduces the size of the condenser lens 17 so that the condenser lens 17 can be arranged as close as possible to the reflective light valve 18. Further, the eccentric amount of the optical axis of the illumination optical system 10 shown in Table 2 is given to the reflection type light valve 18. Thus, vignetting by the condenser lens 17 with respect to the light reflected by the reflective light valve 18 is reduced, and the light utilization efficiency can be increased.

  Next, the effect of the illumination optical system 10 will be described using an example of a spot diagram at each position on the reflective light valve 18. A case where the condenser lens 17 included in the illumination optical system 10 has a biconvex spherical shape (configuration of the present invention) and a case where the condenser lens 17 has an aspherical shape will be described as a comparison.

  FIG. 4 is an example of a spot diagram in the case where the condenser lens 17 has a spherical shape with a convex surface on both sides. FIG. 5 is an example of a spot diagram when the condenser lens 17 is aspherical.

  The “position on the screen” shown in FIGS. 4 and 5 means the position on the screen of the image displayed on the screen. 4 and 5 show spot diagrams at positions on the reflective light valve 18 that reflects light corresponding to the “position on the screen”.

  That is, the spot diagram whose position on the screen is “center” is a spot diagram at the center position on the reflective light valve 18 where the projected position reflects light corresponding to the center on the screen. The spot diagram whose position on the screen is “lower right” shows the spot diagram at the end position on the reflective light valve 18 where the projected position reflects light corresponding to the lower right on the screen. Yes.

  As shown in FIG. 4, when the condenser lens 17 has a biconvex spherical shape, the “lower right” spot diameter (1.58 mm) is smaller than the “center” spot diameter (1.71 mm). On the other hand, as shown in FIG. 5, when the condenser lens 17 is aspherical, the “lower right” spot diameter (1.28 mm) becomes larger than the “center” spot diameter (1.08 mm). The reason why the spot diameter when the condenser lens 17 is aspherical is smaller in the vicinity of the center than in the lower right is due to the effect of correcting the spherical aberration of the aspherical shape.

  The smaller the spot diameter, the higher the illuminance. That is, by setting the shape of the condenser lens 17 to a biconvex spherical shape, the “lower right” illuminance is higher than the “center”.

  Next, the operation and effect of the illumination optical system 10 will be described using an example of illuminance distribution in the reflective light valve 18. 6 and 7 are contour diagrams in which a model of the illumination optical system 10 including the lamp unit 11 and the rod integrator 13 is created on a computer program, and the illuminance distribution on the reflective light valve 18 is graphed by simulation. is there.

  FIG. 6 shows a case where the condenser lens 17 included in the illumination optical system 10 has a biconvex spherical shape (configuration of the present invention). FIG. 7 shows a case where the condenser lens 17 is aspherical for comparison.

  The scales in the longitudinal direction and the lateral direction shown in FIGS. 6 and 7 indicate the positions in the longitudinal direction and the lateral direction on the reflective light valve 18. The origin (0, 0) matches the center position of the reflective light valve 18.

  6 and 7, the lower right side in the drawing indicated by the scale corresponds to the lower right side of the image displayed on the screen. A black frame 182 shown in FIGS. 6 and 7 shows an effective image area of the reflective light valve 18. 6 and 7 show the illuminance at each position normalized by using the maximum illuminance in the reflective light valve 18. Of the illuminance at each position, the darker color portion indicates the portion with higher illuminance.

  As shown in FIG. 6, when the condenser lens 17 has a biconvex spherical shape, the lower left illuminance and the lower right illuminance are higher than the illuminance at the center of the effective image area on the reflective light valve 18. On the other hand, when the condenser lens 17 is aspheric, the lower left illuminance and the lower right illuminance are lower than the illuminance at the center of the effective image area on the reflective light valve 18. In the illuminance distribution when the condenser lens 17 is aspherical, the vicinity of the center is higher than that of the lower right. Is to improve.

  As described above, the illumination optical system 10 has an illuminance distribution on the reflective light valve 18 because the optical axis is decentered with respect to the reflective light valve 18 and the condenser lens 17 has a biconvex spherical shape. Is different from the conventional one. That is, according to the illumination optical system 10, in the illuminance distribution on the reflective light valve 18, the illuminance at the position corresponding to the lower right can be made higher than the position corresponding to the center of the projection image. By using this illumination optical system 10, it is possible to reduce the illuminance unevenness of the projected image on the screen.

  Further, the illumination optical system 10 sets the distance from the center of the condenser lens 17 to the center of the reflective light valve 18 to 20 mm or less. As a result, the size of the condenser lens 17 can be reduced. By reducing the size of the condenser lens 17, the cost of the illumination optical system 10 can be reduced.

  The illumination optical system 10 has a rotation angle of the optical axis of the illumination optical system 10 with respect to the plane parallel to the reflection type light valve 18 of 24 degrees or more, and a rotation angle with respect to the plane perpendicular to the reflection type light valve 18 of 15 degrees. That's it. In this way, by shifting the optical axis of the illumination optical system 10 with respect to the reflective light valve 18, the light reflected by the reflective light valve 18 is efficiently guided to the projection lens. When the reflected light from the reflective light valve 18 is efficiently guided to the projection lens, the image displayed on the screen can be brightened.

The illumination optical system 10 has the following conditional expression when the light spot diameter at the lower right position of the reflective light valve 18 is φ1 and the light spot diameter at the central position of the reflective light valve 18 is φ2. 1
(Condition 1) φ1 / φ2 <1

  That is, the illumination optical system 10 is a spot at a position on the reflective light valve 18 where the spot diameter (Φ1) at a position corresponding to the lower right position of the image projected on the screen corresponds to the center position. It is smaller than the diameter Φ2. Thereby, when the illumination optical system 10 is mounted on the image display device, it is possible to reduce unevenness of illumination on the screen caused by the dust-proof glass.

  In addition, the illumination optical system 10 can use a DMD (Digital Micromirror Device) as the reflective light valve 18, thereby reducing the size of the illumination optical system 10, thereby reducing the size of the image display device.

  In the illumination optical system 10, an ultra-high pressure mercury lamp can be used for the lamp unit 11. When an ultra high pressure mercury lamp is used, a light image with high light utilization efficiency can be formed. Further, a solid light source such as an LD or LED can be used for the lamp unit 11. When these solid-state light sources are used, it is possible to form an image having a long life and good color reproducibility as compared with the case of using an ultrahigh pressure mercury lamp.

Embodiment of Image Display Device Next, an embodiment of an image display device according to the present invention will be described. FIG. 8 is an optical arrangement diagram showing an example of arrangement of optical elements constituting the projector 100 that is the image display apparatus according to the present embodiment.

  The projector 100 includes the illumination optical system 10, the projection lens system 20, the concave reflecting mirror 21, and the cover glass 22 that have already been described. The projection lens system 20, the concave reflecting mirror 21, and the cover glass 22 constitute a projection optical system.

  The projection lens system 20 is a projection lens group for projecting light reflected by the reflective light valve 18 included in the illumination optical system 10 onto a screen (not shown). In FIG. 8, a lens barrel that maintains the projection lens group in a predetermined arrangement is not shown.

  The concave reflecting mirror 21 is a mirror that reflects light that has passed through the projection lens system 20 to a screen (not shown).

  The cover glass 22 is dust-proof glass installed at the opening of the projector 100. The cover glass 22 prevents dust and the like from entering the projector 100.

  In the projector 100, light projected on a screen (not shown) passes through the cover glass 22. The projector 100 is a close-range projector with a short installation distance from the screen. Therefore, the angle at which the light reflected by the concave reflecting mirror 21 enters the cover glass 22 is increased. For example, the angle (incident angle) at which the light rays corresponding to the lower ends of the image displayed on the screen enter the cover glass 22 is about 80 degrees.

  Here, the angular characteristics of the transmittance when a special antireflection film is applied to the cover glass 22 are shown in FIG. As can be seen from FIG. 9, the transmittance falls to about 50% near an incident angle of 80 degrees. This means that, in the case of a close-range projector, both ends on the lower side of the projected image are particularly dark due to the transmittance loss due to the cover glass 22.

  The illumination optical system 10 is a non-telecentric optical system. In such a non-telecentric illumination optical system 10, it is necessary to avoid the occurrence of “vignetting” due to the condenser lens 17 in the light reflected by the reflective light valve 18. Therefore, the condenser lens 17 included in the illumination optical system 10 is provided with a notch portion 171 in which a part thereof is notched (see FIG. 1). However, by providing the notch 171, the illuminance at the position on the reflective light valve 18 corresponding to the lower right position of the projected image on the screen is reduced.

  Even if the illumination optical system 10 is a non-telecentric optical system using a concave reflecting mirror, the concave reflecting mirror requires a notch. As a result, the illuminance at the position on the reflective light valve 18 corresponding to the lower right position of the projected image on the screen decreases.

  The projector 100 includes an illumination optical system 10 that reduces the above-described decrease in illuminance. Therefore, the projector 100 can reduce uneven illuminance of the projected image on the screen.

  In particular, even if the projector 100 is a very close distance projector in which the maximum incidence of light on the cover glass 22 is 70 degrees or more, it is possible to reduce unevenness in the illuminance of the projected image on the screen.

DESCRIPTION OF SYMBOLS 10 Illumination optical system 11 Lamp unit 12 Color wheel 13 Rod integrator 14 1st relay lens 15 2nd relay lens 16 Folding mirror 17 Condenser lens 18 Reflection type light valve 19 Relay lens

JP 2013-88727 A

Claims (8)

An illumination optical system that is used in an image display device having a dustproof member in an optical path from a projection optical system to a projection surface and guides light emitted from a light source to a reflective light valve,
The illumination optical system sequentially changes the illuminance distribution of the light reflected by the rod integrator, relay lens, mirror, and light that irradiates light with uniform illuminance distribution by multiple reflection along the light traveling direction. A condenser lens,
The condenser lens is a biconvex spherical lens,
The light collected by the condenser lens has the following conditional expression 1 when the spot diameter of the light at the end position of the reflective light valve is φ1 and the spot diameter of the light at the center position is φ2.
φ1 / φ2 <1
The filling,
Wherein the illumination on the reflection-type light valve that will be illuminated by the illumination optical system, illumination optical system, wherein the high at the end position than the center position of the reflection type light valve. The center position is a position on the reflection type light valve in which the light valve image formed by the reflecting light corresponding to the center when it is projected on the projection surface,
It said end position is a position on the reflection type light valve in which the light valve image formed by the reflecting light corresponding to the bottom right when being projected on the projection surface,
The illumination optical system according to claim 1. The distance from the center of the condenser lens to the center of the reflective light valve is 20 mm or less,
The rotation angle of the optical axis of the illumination optical system with respect to the plane parallel to the reflective light valve is 24 degrees or more,
The rotation angle of the illumination optical system with respect to a plane perpendicular to the reflective light valve is 15 degrees or more.
The illumination optical system according to claim 1 or 2. The reflective light valve is a DMD.
The illumination optical system according to any one of claims 1 to 3. The light source is an ultra-high pressure mercury lamp or a solid light source,
The illumination optical system according to any one of claims 1 to 4. An image display apparatus having a reflection type light valve and having an incident angle of 70 degrees or more with respect to a dustproof member disposed at a position where light projected from a projection optical system toward a projection surface passes. An illumination optical system used,
The illumination optical system sequentially changes the illuminance distribution of the light reflected by the rod integrator, relay lens, mirror, and light that irradiates light with uniform illuminance distribution by multiple reflection along the light traveling direction. A condenser lens,
The condenser lens is a biconvex spherical lens,
The light condensed by the condenser lens has the following conditional expression 1 when the spot diameter of the light at the end position of the light valve is φ1 and the spot diameter of the light at the center position is φ2.
φ1 / φ2 <1
The filling,
An illumination optical system, wherein an illuminance on the reflective light valve illuminated by the illumination optical system is higher at an end position than a center position of the reflective light valve. An illumination optical system having a light source, a rod integrator, a relay lens, a mirror, a condenser lens, and a reflective light valve;
A projection optical system for enlarging and projecting an image formed in the reflective light valve;
An image display apparatus which have a,
The illumination optical system is the illumination optical system according to any one of claims 1 to 5 .
An image display device characterized by that. Has a dustproof member comprising a plate-like cover glass, the cover glass is disposed at a position where light is projected toward the projection surface from said projection optical system passes, with respect to the cover glass, the incident of the light The angle is 70 degrees or more,
The image display device according to claim 7.

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