JP2003161917A - Projection type image display device and image display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that light loss occurs due to the variation of an angle of light incident on the multilayer film of a polarizing beam splitter to composite an optical path in a projection type image display device. <P>SOLUTION: The projection type image display device has illumination optical systems 1 to 5b, a color separation composition optical system 7 which separates illumination light from the illumination optical system into a plurality of color light beams, makes each color light beam incident on image display elements 8r to 8b provided for each color light beam, and composites image light emitted from the image display elements and having a plurality of colors, and a projection optical system 10 which projects and displays the image light composited by the color separation composition optical system. Polarizing elements Pr, Pg and Pb which transmits only specific polarized component light are provided between the color separation composition optical system and the image display elements. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection-type image display device which decomposes illumination light from an illumination optical system into a plurality of color lights and synthesizes the respective color lights modulated by an image display element to project and display an image. Is.

[0002]

2. Description of the Related Art An illumination optical system for illuminating an image display device,
2. Description of the Related Art Conventionally, a projection type image display device has been used, which uses an image display element such as a liquid crystal display that modulates the polarization state of illumination light to generate image light and magnifies and projects the image light from the image display element.

Then, a so-called reflection type image display element is used, in which the side on which the illumination light from the illumination optical system enters the image display element and the side on which the image light modulated by the image display element exits are the same. The image display device used is proposed in Japanese Patent Laid-Open No. 10-319344.

FIG. 14 shows the configuration of a conventional projection type image display device.
Is shown in. In this figure, 101 is a light source and 10
2 is a reflector, 103 is a filter, 104,
Reference numeral 106 is a fly-eye lens. Further, 105 is a mirror, 107 is a polarization beam splitter, 108 is a color separation / combination prism, 109r, 109g and 109b are image display elements, and 110 is a projection lens.

Here, the optical path IL of the illumination optical system and the optical path PL of the projection optical system are combined by a polarization beam splitter 107 so as to pass through a single color separation / combination prism 108.

[0006]

However, since the polarization beam splitter for synthesizing the optical paths is composed of a multilayer film, if the angle of the light incident on the multilayer film varies and deviates from the design angle (for example, 45 degrees). , P polarization component and S
There is a problem in that the efficiency of separation into polarized light components varies, light loss occurs, and only a dark image can be projected as an image display device.

[0007]

In order to solve the above problems, in the first invention of the present application, an illumination optical system and illumination light from the illumination optical system are decomposed into a plurality of color lights, and the respective color lights are separated. A color separation / combination optical system that combines the image lights of the plurality of colors emitted from these image display elements with the incident light on the image display element provided for each color light, and projects the image light combined by this color separation / combination optical system. In a projection type image display device having a projection optical system for displaying, only a specific polarized component light is transmitted between the color separation / combination optical system and the image display element (that is, a polarized component other than the specific polarized component light). A polarizing element that blocks light is provided.

In the second invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and the respective color lights are made incident on the image display element provided for each color light. , A projection type image display device having a color separation / combination optical system for combining the image lights of a plurality of colors emitted from these image display elements and a projection optical system for projecting and displaying the image lights combined by the color separation / combination optical system At
Between the illumination optical system and the color separation / combination optical system, the illumination light from the illumination optical system is reflected with a reflectance close to 100% to be guided to the color separation / combination optical system, and the image light from the color separation / combination optical system Is provided to the projection optical system, and the optical path of the illumination light and the optical path of the image light in the light guiding element and the color separation / combination optical system are different from each other, and the color separation / combination optical system and the image are combined. A polarizing element that transmits only specific polarized component light is provided between the display element and the display element.

Further, in the third invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and the respective color lights are made incident on the image display element provided for each color light. , A projection type image display device having a color separation / combination optical system for combining the image lights of a plurality of colors emitted from these image display elements and a projection optical system for projecting and displaying the image lights combined by the color separation / combination optical system At
Between the illumination optical system and the color separation / combination optical system, the illumination light from the illumination optical system is reflected with a reflectance close to 100% to be guided to the color separation / combination optical system, and at the same time, the image light from the color separation / combination optical system. A light guide element for transmitting light to the projection optical system, and a light guide element for a light beam along the center line of the illumination light flux in the illumination optical system,
When the trace lines in the color separation / combination optical system and projection optical system are used as the reference axes of the entire system, the reference axis in the color separation / combination optical system (or illumination optical system) and the reference axis in the projection optical system are displayed as images. A polarizing element that is inclined with respect to the normal line of the display surface of the element and that transmits only a specific polarized component light is provided between the color separation / combination optical system and the image display element.

In the second and third aspects of the invention, as the light guide element, for example, the first surface on which the illumination light is incident, and the illumination light is emitted toward the color separation / combination system and the color separation / combination is performed. The second which makes the image light from the optical system enter
Surface and the illumination light incident from the first surface are reflected toward the second surface with a reflectance close to 100%, and the image light incident from the second surface is emitted toward the projection optical system. It can be configured by a prism-shaped optical element having a third surface.

In the fourth invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and the respective color lights are made incident on the image display element provided for each color light. , A projection type image display device having a color separation / combination optical system for combining the image lights of a plurality of colors emitted from these image display elements and a projection optical system for projecting and displaying the image lights combined by the color separation / combination optical system At
Between the illumination optical system and the color separation / combination optical system, the illumination light from the illumination optical system is transmitted to the color separation / combination optical system, and the image light from the color separation / combination optical system is reflected with a reflectance close to 100%. A light guide element that guides the light to the projection optical system so that the light path of the illumination light and the light path of the image light in the light guide element and the color separation / combination optical system are different from each other, and the color separation / combination optical system and the image display A polarizing element that transmits only specific polarized component light is provided between the element and the element.

Further, in the fifth invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and the respective color lights are made incident on the image display element provided for each color light. , A projection type image display device having a color separation / combination optical system for combining the image lights of a plurality of colors emitted from these image display elements and a projection optical system for projecting and displaying the image lights combined by the color separation / combination optical system At
Between the illumination optical system and the color separation / combination optical system, the illumination light from the illumination optical system is transmitted to the color separation / combination optical system, and the image light from the color separation / combination optical system is reflected with a reflectance close to 100%. A light guide element for guiding the light to the projection optical system, and a light guide element for a light beam along the center line of the illumination light flux in the illumination optical system,
When the trace lines in the color separation / combination optical system and projection optical system are used as the reference axes of the entire system, the reference axis in the color separation / combination optical system (or illumination optical system) and the reference axis in the projection optical system are displayed as images. A polarizing element that is inclined with respect to the normal line of the display surface of the element and that transmits only a specific polarized component light is provided between the color separation / combination optical system and at least one image display element.

In the fourth and fifth aspects of the invention, the light guide element may be, for example, a first light source that receives illumination light and reflects image light with a reflectance close to about 100%.
From the first surface, the second surface from which the illumination light incident from the first surface is emitted toward the color separation / combination optical system, and the image light from the color separation / combination optical system is incident from the second surface. It can be configured by a prism-shaped optical element having a third surface which makes the image light incident and reflected by the first surface emerge toward the projection optical system.

Here, since the image display element modulates the polarization state of light, a polarization element for displaying an image is required between the illumination optical system and the projection optical system. According to the invention, by providing this polarizing element between the color separation / combination optical system and the image display element, an optical element in which an illumination optical path and a projection optical path overlap each other (an element or a light guide element constituting the color separation / combining optical system). It is possible to improve the contrast of the image by eliminating the influence of internal distortion in (1) and the disorder of the polarization state in the optical multilayer film.

Further, according to the second to fifth inventions of the present application, it is possible to separate the optical path of the illumination light and the optical path of the image light without providing a polarization beam splitter as in the prior art. In addition, the light guide element allows illumination light from the illumination optical system or image light from the color separation / combination optical system to be approximately 100%.
Since the light is reflected with a reflectance close to that of the above and guided to the color separation / combination optical system or the projection optical system, it is possible to improve the light utilization efficiency as compared with the conventional projection type image display device and obtain a bright and high-definition display image. Is possible.

Further, as in the third and sixth inventions, the reference axis in the color separation / combination optical system (or the illumination optical system) and the reference axis in the projection optical system are respectively defined by normal lines to the display surface of the image display element. If it is set to be inclined with respect to, the projection optical system can be downsized.

Here, when the reference axis of the illumination optical system is arranged at an inclination angle θ with respect to the normal line of the image display element, the reference axis of the projection optical system also falls on the opposite side to the normal line of the image display element. It is arranged at an angle θ. At this time, when the tilt angle θ is increased, the angle 2θ formed by the reference axis of the illumination light path and the reference axis of the projection light path is increased, and the angle ω at which the projection light path (or the illumination light path) is incident on the light guide element is decreased. It is possible to make the transmittance even more uniform depending on the incident angle of all the rays that pass through the element. Further, in the illumination optical system, the smaller the F number of the illumination optical system, the better the efficiency.

On the other hand, in the decentering optical system, the smaller the tilt angle θ of the object surface (image display element), the smaller the amount of decentration aberrations, and the larger the F number of the projection optical system, the easier the correction of aberrations. .

Note that the projection optical system is a decentered optical system having at least one rotationally asymmetric surface or a plurality of optical elements having mutually different rotational symmetry axes, so that keystone distortion or the like caused by tilting the projection optical system, etc. It becomes possible to correct the eccentric aberration.

Further, when the light guide element is formed in a wedge shape, an auxiliary optical element for refracting and transmitting the image light emitted from the light guide element is provided between the light guide element and the projection optical system with respect to the light guide element. Or an auxiliary optical element that refracts and transmits the illumination light from the illumination optical system is placed between the light guide element and the illumination system with an air gap between the light guide element and the illumination system. By doing so, it becomes possible to mitigate the aberration generated in the wedge shape.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIG. 1 shows the configuration of a projection type image display apparatus according to the first embodiment of the present invention. In the figure, 1 is an illumination light source composed of a high pressure mercury lamp or the like, and 2 is a reflector for radiating the light from the light source 1 in a predetermined direction.

Reference numeral 3 denotes an integrator for forming a uniform illumination area, which is composed of fly-eye lenses 3a and 3b.

Reference numeral 4 is a polarization conversion element for aligning unpolarized light in a predetermined polarization direction, and includes a polarization separation film 4a and a reflection film 4b.
/ 2 phase plate 4c.

Reference numeral 5 denotes a condensing optical system for condensing the illumination light,
It is composed of lenses 5a and 5b and a mirror 5c. The light source 1 to the lens 5b constitute an illumination optical system referred to in the claims.

Reference numeral 6 denotes an optical path prism (light guide element) for setting the optical paths of the illumination optical system and the projection optical system so as to pass through one color separation / combination optical system.

Reference numeral 7 denotes a dichroic prism (color separation / combination optical system) for decomposing the optical path into three colors of R, G, and B and combining them again. In this embodiment, three prisms are combined to form a predetermined dichroic prism. A dichroic film is vapor-deposited on the combined surface.

Reference numerals 8r, 8g and 8b are reflection type image display elements for each color light which are composed of a liquid crystal display or the like, and are not shown in the figure such as personal computer, television, video and DV.
It is driven by a signal corresponding to image information from an image information supply device such as a D player, and reflects the incident illumination light of each color, modulates it, and emits it.

Reference numeral 9 denotes an auxiliary prism (auxiliary optical element), 10
Is an eccentric projection lens (projection optical system).

Pr, Pg, and Pb are polarizing plates (polarizing elements) arranged between the dichroic prism 7 and the reflective image display elements 8r to 8b, respectively.

Next, the optical operation of the image display device configured as described above will be described. The illumination luminous flux radially emitted from the light source 1 is reflected by the reflector 2 and condensed toward the fly-eye lens 3a. This illumination luminous flux is separated into a plurality of luminous fluxes by the fly-eye lens 3a, and then the fly-eye lens 3b, the lenses 5a, 5
By the action of b, they are superimposed on the image display elements 8r, 8g, 8b to form a uniform illumination area on the image display element.

A large number of light beams emitted from the fly-eye lens 3b are separated into P-polarized light and S-polarized light by the polarization separation film 4a corresponding to each light beam. P-polarization is 1/2 phase plate 4
It is converted into a polarized light component in the same direction as the S-polarized light by c, and the S-polarized light is reflected by the reflection film 4b and emitted in the same direction as a predetermined polarized light.

As shown in FIG. 2, the illumination light beam is incident on the first surface 6a and the second surface 6b of the optical path prism 6 at an angle satisfying the condition of total reflection and is totally reflected. This gives about 100
After the reflection with a reflectance close to%, the optical path is bent, the light is emitted from the third surface 6c.

In this embodiment, the case where the illumination light is totally reflected by the second surface 6b of the optical path prism 6 will be described. However, the reflection on the second surface 6b is outside the second surface 6b. It may be reflected by a mirror coat formed by vapor deposition or the like on a part of the surface.

Further, in the present embodiment, as the dichroic prism 7, a 3P prism composed of three prisms (first to third prisms P1 to P3) is used.

In FIG. 2, the first surface 7 of the first prism P1.
The B (blue) light incident from a is reflected by the first dichroic surface 7db, and the R (red) and G (green) lights are transmitted.

The light of B is reflected by the first surface 7a with a reflectance close to 100% (for example, total reflection), and then the second surface 7b.
From the light source, passes through the polarizing plate Pb, and reaches the B image display element 8b.

The R and G lights transmitted through the first dichroic surface 7db have a slight air gap between them and the third surface 7c of the second prism P2.
R light is reflected by the second dichroic surface 7dr, and G light is transmitted.

The R light is reflected by the third surface 7c at a reflectance close to 100% (for example, total reflection), then emitted from the fourth surface 7d, transmitted through the polarizing plate Pr, and displayed as an image for R. Element 8
to r.

The G light which has passed through the second dichroic surface 7dr enters the third prism P3, then exits from the fifth surface 7e, passes through the polarizing plate Pg, and passes through the G image display element 8.
to g.

The illumination light of each color incident on each image display element is
The polarization state is modulated and reflected by each image display element driven by a signal corresponding to the image information.

The image light modulated and reflected by each image display element is reflected in a direction different from the incident direction of the illumination light,
The light passes through the polarizing plates Pr to Pb and enters the dichroic prism 7, and then passes through the surfaces in the reverse order of the above-described color separation to be combined into one again and exits.

The light emitted from the dichroic prism 7 is passed through the optical path prism 6 from the third surface 6c to the second surface 6b.
In, the light enters at an angle smaller than the angle satisfying the condition of total reflection, passes through the second surface 6b, and exits.

The light emitted from the optical path prism 6 passes through the auxiliary prism 9 while being refracted, and the eccentric projection lens 1 shown in FIG.
0 projects it as a full-color image on a screen (not shown).

Here, in FIG. 1, assuming that the reference axis of the illumination optical system is the central axis of the illumination light beam, the reference axis of the optical system is a fly eye provided with a light ray along the optical axis of the reflector 2 thereafter. Illumination optical system other than lenses 3a and 3b (5
a, 5b, 5c), the optical path prism 6, the dichroic prism 7, the image display elements 8r to 8b, the auxiliary prism 9, and the decentering projection lens 10 can be considered as straight lines traced by light rays.

Based on this, in FIG. 1, IL is set as the reference axis of the illumination optical system, and P is set as the reference axis of the projection optical system.
L is set.

In the present embodiment, as shown in FIG. 2, the reference axis after color separation of the illumination optical system (that is, the reference axis of the color separation / combination optical system) IL and the reference axis PL of the projection optical system are each an image. The display elements 8r to 8b are set so as to be inclined by θ with respect to the normal line of the display surface. As a result, the angle formed by the reference axis IL of the illumination optical system and the reference axis PL of the projection optical system becomes 2θ.

When the tilt angle θ is increased, the angle 2θ formed by the reference axis of the illumination light path and the reference axis of the projection light path increases,
The angle ω at which the image light (or the illumination light) is incident on the optical path prism 6 becomes small, and the transmittance depending on the incident angles of all the light rays passing through the optical path prism 6 can be made more uniform. Further, in the illumination optical system, the smaller the F number of the illumination optical system, the better the efficiency.

On the other hand, in the decentering optical system, the smaller the tilt angle θ of the object surface (image display element), the smaller the amount of decentering aberration, and the larger the F number of the decentering projection lens 10, the easier the aberration correction.

As described above, the polarizing plates Pr to Pb are provided between the dichroic prism 7 and the image display elements 8r to 8b, and serve as a polarizer for illumination light and an analyzer for projection light (image light). For this reason, light that is not modulated in the image display element (exits in the same polarization direction as the incident polarization direction) displays white, and light that is modulated and whose polarization direction is rotated by 90 degrees displays black. To do. At this time, the transmission direction of the polarizing plate may be parallel to the polarization direction aligned by the polarization conversion element, or may be different from the polarization direction aligned by the polarization conversion element by providing a phase plate in the optical path after color separation.

Since each of the image display elements 8r to 8g modulates the polarization state of light as described above, a polarizing plate for displaying an image is required between the illumination optical system and the projection optical system.
In the present embodiment, by providing the polarizing plates Pr to Pb between the dichroic prism 7 and the image display elements 8r to 8b, the interior of the dichroic prism 7 or the optical path prism 6 in which the illumination optical path and the projection optical path overlap each other. It is possible to prevent the influence of the distortion and the disorder of the polarization state in the optical multilayer film, and it is possible to improve the contrast of the image.

Further, in this embodiment, the illumination light from the illumination optical system is reflected between the illumination optical system and the dichroic prism 7 with a reflectance close to 100% to be guided to the dichroic prism 7 and at the same time. Since the optical path prism 6 that transmits the image light emitted from the optical path to the eccentric projection lens 10 side is provided, the optical path of the illumination light and the optical path of the image light in the optical path prism 6 and the dichroic prism 7 are made different from each other. It is possible to separate the optical path of the illumination light and the optical path of the image light without providing a polarization beam splitter as in the conventional case.
Moreover, the illumination light from the illumination optical system is reflected by the optical path prism 6 at a reflectance close to 100% to be guided to the dichroic prism 7, and the image light from the image display elements 8r to 8b is directed to the eccentric projection lens 10. Can be transmitted.

Therefore, the utilization efficiency of light can be improved as compared with the conventional projection type image display device, and a bright display image can be obtained.

Further, in this embodiment, the decentering projection lens 1 is used.
0 is an eccentric optical system having at least one rotationally asymmetric surface or a plurality of optical elements having mutually different rotational symmetry axes, so that eccentric aberration such as keystone distortion caused by tilting the reference axis of the projection optical system Can be corrected.

Further, in this embodiment, the optical path prism 6 is formed in a wedge shape, but between the optical path prism 6 and the eccentric projection lens 10, an auxiliary for refracting and transmitting the image light emitted from the optical path prism 6 is assisted. Since the prism 9 is arranged with an air gap with respect to the optical path prism 6, it is possible to reduce the aberration generated in the wedge shape.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
1 illustrates a configuration of a projection-type image display device that is an embodiment. The same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment and will not be described.

In this embodiment, between the dichroic prism 7 and the image display elements 8r, 8g, 8b, dichroic filter units PDr, PDg, PD with polarizing plates are provided.
The difference from the first embodiment is that the color adjustment is performed by providing b.

In this embodiment, dichroic filter units PDr, PDg, PDb are provided between the polarizing plate and the image display element in each color optical path and used in combination with the phase plate. In addition, the dichroic filter unit P
The polarizing plates of Dr, PDg and PDb also serve as a polarizer for the illumination light and an analyzer for the projection system.

FIG. 4A shows a detailed view of the G optical path. Dichroic filter unit with polarizing plate PDg
Is constituted by laminating a polarizing plate Pg, a first ¼ phase plate R1, a dichroic filter Dg, and a second ¼ phase plate R2.

As a result, the light incident as the illumination light (I) is adjusted into linearly polarized light (.) By the polarizing plate Pg, and then converted into circularly polarized light (.largecircle.) By the first phase plate R1.
It is incident on the dichroic filter Dg.

The dichroic filter Dg reflects light (C) having an unnecessary wavelength component and transmits the wavelength component to be used. The polarization direction (∘) of the light reflected by the dichroic filter Dg is converted by the first ¼ phase plate R1 into the polarization direction (|) rotated by 90 ° with respect to the transmission axis of the polarizing plate Pg, and the reflected light is It is absorbed by the polarizing plate Pg.

Further, the light transmitted through the dichroic filter Dg is converted into linearly polarized light (|) by the second quarter-wave plate R2 and is incident on the image display element 8g.

The light (P) reflected by the image display element 8g and whose polarization direction has not changed is again reflected by the second quarter-wave plate R2.
Then, it becomes circularly polarized light (○), passes through the dichroic filter Dg, and then passes through the first ¼ phase plate R1 to be converted into linearly polarized light having the same polarization direction (·) as the illumination light (I), and the polarizing plate Permeate Pg.

The light (P ') whose polarization direction is rotated by 90 degrees by the image display element 8g has its polarization direction rotated by 90 degrees (.), And therefore the second phase plate R2, the dichroic filter Dg and the first phase plate R2. After passing through the phase plate R1, it is converted into a polarization direction (|) orthogonal to the illumination light (I) and is absorbed by the polarizing plate Pg.

Also in the R and B optical paths, dichroic filter units PDr and PD with polarizing plates having the same structure as G
b is provided.

Here, here, the dichroic filter D
The characteristics of g, Db, and Dr are such as shown in FIG. 5 so as to cut off the light in the wavelength band (cyan, orange) at the RGB boundary portion of the illumination light.

In FIG. 5, the characteristic obtained by combining the dichroic films 7db and 7dr in the dichroic prism 7 is also shown by a dotted line.

As a modified example of this embodiment, a structure in which the second phase plate is omitted as shown in FIG. 4B may be adopted. In this case, the image display elements 8r, 8g, 8b have a function of modulating circularly polarized light.

(Third Embodiment) FIG. 6 shows a third embodiment of the present invention.
1 illustrates a configuration of a projection-type image display device that is an embodiment. The same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment and will not be described.

In this embodiment, a chromatic phase filter CF for converting the polarization direction of light in a specific wavelength band by 90 degrees in the illumination optical system.
Is different from the first embodiment in that the dichroic prism 37 having four triangular prisms and having a dichroic surface crossing in an X shape is used.

Here, the operation of the dichroic prism 37 will be described. In the figure, of the light incident from the first surface 37a, the light reflected by the first dichroic surface 37db is transmitted through the second surface 37c, is transmitted through the polarizing plate Pb, and is further displayed as an image for B light. It reaches the element 8b.

The light reflected by the second dichroic surface 37dr passes through the third surface 37b and the polarizing plate Pr, and then reaches the image display element 8r for R light.

The light transmitted through both the first dichroic surface 37db and the second dichroic surface 37dr passes through the fourth surface 37d and the polarizing plate Pg, and then reaches the image display element 8g for G light.

The color phase filter CF rotates the polarization direction by 90 degrees in a specific wavelength band (for example, G band) when light aligned in a certain polarization direction is incident. Figure 7
This is shown in (a) and (b).

FIG. 7A shows the intensity of the polarized component parallel to the polarization direction of the incident light, and FIG. 7B shows the intensity of the polarized component perpendicular to the incident polarization direction.

Since the light having the characteristics shown in FIGS. 7A and 7B is emitted from the color phase filter CF, in the present embodiment, the G polarization direction passing through the dichroic prism 7 and the R and B polarization directions. The polarization direction is different by 90 degrees. Therefore, as shown in FIG. 8, the transmission axis Qg of the polarizing plate Pg provided in the G optical path and the transmission axes Qr, Qb of the polarizing plates Pr, pb provided in the R and B optical paths differ by 90 degrees. It is in the direction.

Further, a phase plate may be provided in the G or R, B optical path to set the polarization direction to a predetermined direction.

As shown here, the polarization directions of the G, R, and B lights are made different by 90 degrees, and a large amount of light transmitted through the dichroic film forming the dichroic prism 7 is P.
By adopting a configuration in which the dichroic film is transmitted as polarized light, the efficiency of the dichroic film can be further increased.

Further, as a configuration different from this embodiment, a color phase filter CF is provided between the optical path prism 6 and the dichroic prism 7, and each color light is transmitted / reflected in the same polarization direction in the optical path prism 6 to be dichroic. In the prism 7, the P-polarized component and the S-polarized component may be selectively used depending on the color light.

As described above, in the configuration using the color phase filter CF, not only the dichroic prism including the cross prism shown in the present embodiment but also the dichroic prism including the 3P prism as shown in the first embodiment is used. Any structure having a decomposing effect has the effect shown here.

(Fourth Embodiment) FIG. 9 shows a fourth embodiment of the present invention.
1 illustrates a configuration of a projection-type image display device that is an embodiment.

In this embodiment, the first embodiment is different from the first embodiment except that the light passing through the optical path prism 6 is different.
Since it is the same as the embodiment, the first common component is
The same reference numerals as in the embodiment are attached and replaced with the description.

In the present embodiment, the illumination light that has passed through the lens 5b first enters the first surface 6b 'of the optical path prism 6, passes through the second surface 6c', and enters the dichroic prism 7.

In the dichroic prism 7, as in the first embodiment, the illumination light is separated into R, G, and B color lights, transmitted through the polarizing plates Pr, Pg, Pb, and image display elements 8r to 8b for each color. To the polarizing plates Pr, Pg,
The R, G, and B lights that have passed through Pb are combined and incident again from the second surface 6c 'of the optical path prism 6.

The image light incident on the optical path prism 6 is totally reflected by the first surface 6b ', exits from the third surface 6a', and is projected by the eccentric projection lens 10.

In the present embodiment, the illumination light from the illumination optical system is transmitted to the dichroic prism 7 between the illumination optical system and the dichroic prism 7, and the image light from the dichroic prism 7 is reflected to almost 100%. An optical path prism 6 that reflects light at a high rate and transmits it toward the eccentric projection lens 10 is provided, and the optical path of illumination light and the optical path of image light in the optical path prism 6 and the dichroic prism 7 are made different from each other. It is possible to separate the optical path of the illumination light and the optical path of the image light without providing a polarization beam splitter as in the conventional case. Moreover, the dichroic prism 7 is formed by the optical path prism 6.
It is possible to reflect the image light from the optical system with a reflectance close to 100% and guide it to the eccentric projection lens 10.

Therefore, the utilization efficiency of light can be improved as compared with the conventional projection type image display device, and a bright display image can be obtained.

In the present embodiment, an auxiliary optical element for refracting and transmitting the illumination light from the illumination optical system is provided between the optical path prism 6 and the illumination optical system with an air space provided for the optical path prism 6. You may arrange.

Further, in the present invention, the arrangement of the image display elements for each color of light is not limited to the arrangement described in each of the above embodiments, but may be set arbitrarily.

[0089]

As described above, according to the first to fifth inventions of the present application, in the projection type image display device which requires the polarizing element by including the image display element for modulating the polarization state of light, Since this polarizing element is provided between the color separation / combination optical system and the image display element, an optical element in which the illumination optical path and the projection optical path overlap each other (such as an element or a light guide element constituting the color separation / combining optical system). It is possible to prevent the influence of the internal distortion in 1) and the disorder of the polarization state in the optical multilayer film, and to improve the contrast of the image.

According to the second to fifth inventions of the present application,
Without providing a polarizing beam splitter as in the past,
It is possible to separate the optical path of the illumination light and the optical path of the image light. Moreover, since the illumination light from the illumination optical system or the image light from the color separation / combination optical system is reflected by the light guide element with a reflectance close to about 100%, the light is guided to the color separation / combination optical system or the projection optical system. The light utilization efficiency can be improved as compared with the projection type image display device, and a bright and high-definition display image can be obtained.

Further, as in the third and sixth inventions, the reference axis in the color separation / combination optical system (or the illumination optical system) and the reference axis in the projection optical system are respectively defined by normal lines to the display surface of the image display element. The projection optical system can be downsized by setting it so as to incline with respect to.

Note that the projection optical system is a decentered optical system having at least one rotationally asymmetric surface or a plurality of optical elements having mutually different rotational symmetry axes, so that keystone distortion or the like caused by tilting the projection optical system The eccentric aberration can be corrected.

When the light guide element is formed in a wedge shape, an auxiliary optical element for refracting and transmitting the image light emitted from the light guide element is provided between the light guide element and the projection optical system with respect to the light guide element. Or an auxiliary optical element that refracts and transmits the illumination light from the illumination optical system is placed between the light guide element and the illumination system with an air gap between the light guide element and the illumination system. By doing so, the aberration generated in the wedge shape can be alleviated.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a projection type image display device according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of the projection type image display device according to the first embodiment.

FIG. 3 is a diagram showing a configuration of a projection type image display device which is a second embodiment of the present invention.

FIG. 4 is a diagram illustrating an optical action of a dichroic filter unit with a polarizing plate according to the second embodiment.

FIG. 5 is a diagram illustrating characteristics of the dichroic filter according to the third embodiment.

FIG. 6 is a diagram showing a configuration of a projection type image display device which is a third embodiment of the present invention.

FIG. 7 is a characteristic diagram of the color phase filter in the third embodiment.

FIG. 8 is a diagram illustrating a transmission direction of a polarizing plate according to the third embodiment.

FIG. 9 is a diagram showing a configuration of a projection type image display device which is a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a conventional projection-type image display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 light source 2 reflector 3 integrator 4 polarization conversion element 5 condensing optical system 6 optical path prism 7 dichroic prisms 8r, 8g, 8b image display element 9 auxiliary prism 10 eccentric projection lens IL reference axis of illumination optical system PL reference axis of projection optical system Pr, Pg, Pb Polarizing plates PDr, PDg, PDb Dichroic filter unit Dr, Dg, Db Dichroic filter CF Chromatic phase filter θ Illumination angle of the reference axis of the illumination optical system (and projection optical system) with respect to the normal line of the image display element

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 5/30 G02B 5/30 2H099 G02F 1/13 505 G02F 1/13 505 1/1335 510 1/1335 510 1/13357 1/13357 G03B 21/00 G03B 21/00 E 33/12 33/12 (72) Inventor Hiroyuki Kodama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Keishi Otaka Tokyo 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H042 CA08 CA12 CA17 2H048 FA11 FA22 GA11 GA23 2H049 BA02 BA03 BA07 BB03 2H088 EA12 EA16 HA10 HA18 HA20 HA23 MA01 MA02 MA05 MA06 MA20 2H091 FA21 FA07 LA11 LA16 LA17 LA18 LA20 MA07 2H099 AA12 BA09 BA17 CA11

Claims (13)

[Claims] 1. An illumination optical system, and the illumination light from the illumination optical system is decomposed into a plurality of color lights, and the respective color lights are made incident on an image display element provided for each color light and emitted from these image display elements. A color separation / combination optical system for combining image lights of a plurality of colors, and a projection optical system for projecting and displaying the image light combined by the color separation / combination optical system. A projection type image display device, characterized in that a polarizing element that transmits only specific polarized component light is provided between the synthetic optical system and the image display element. 2. An illumination optical system, and the illumination light from the illumination optical system is decomposed into a plurality of color lights, and the respective color lights are made incident on an image display element provided for each color light and emitted from these image display elements. And a projection optical system for projecting and displaying the image light combined by the color separation / combination optical system. Between the system and the color separation / combination optical system, the illumination light from the illumination optical system is reflected at a reflectance close to about 100% to be guided to the color separation / combination optical system, and from the color separation / combination optical system. A light guide element for transmitting image light to the projection optical system, wherein an optical path of illumination light and an optical path of image light in the light guide element and the color separation / combination optical system are different from each other, and the color separation Synthetic optics A projection-type image display device, comprising a polarizing element that transmits only a specific polarized component light between the image display element and the image display element. 3. An illumination optical system, and the illumination light from the illumination optical system is decomposed into a plurality of color lights, and the respective color lights are made incident on image display elements provided for each color light, and emitted from these image display elements. And a projection optical system for projecting and displaying the image light combined by the color separation / combination optical system. Between the system and the color separation / combination optical system, the illumination light from the illumination optical system is reflected at a reflectance close to about 100% to be guided to the color separation / combination optical system, and from the color separation / combination optical system. A light guide element for transmitting image light to the projection optical system, the light guide element for a light beam along a center line of an illumination light flux in the illumination optical system, the color separation / combination optical system, and the projection optical system. Trace line at When the reference axis of the entire system, the reference axis in the color separation and synthesis optical system and the reference axis in the projection optical system are respectively inclined with respect to the normal line of the display surface of the image display element, and the color A projection type image display device, characterized in that a polarizing element for transmitting only a specific polarized component light is provided between the disassembling and combining optical system and the image display element. 4. The first light guide element has a first surface on which illumination light enters, and a first surface which emits the illumination light toward the color separation / combination system and allows image light from the color separation / combination optical system to enter. The second surface and the illumination light incident from the first surface are reflected toward the second surface with a reflectance close to about 100%, and the image light incident from the second surface is projected onto the projection optical system. The projection-type image display device according to claim 2 or 3, further comprising a third surface that is emitted toward the. 5. An illumination optical system, and the illumination light from the illumination optical system is decomposed into a plurality of color lights, and the respective color lights are made incident on an image display element provided for each color light and emitted from these image display elements. And a projection optical system for projecting and displaying the image light combined by the color separation / combination optical system. Between the system and the color separation / combination optical system, the illumination light from the illumination optical system is transmitted to the color separation / combination optical system, and the image light from the color separation / combination optical system has a reflectance close to 100%. And a light guide element that guides the light to the projection optical system, and the light path of the illumination light and the light path of the image light in the light guide element and the color separation / combination optical system are different from each other, and Color separation synthesis A projection-type image display device, comprising a polarizing element that transmits only a specific polarized component light between an optical system and the image display element. 6. An illumination optical system, and the illumination light from the illumination optical system is decomposed into a plurality of color lights, and the respective color lights are made incident on an image display element provided for each color light and emitted from these image display elements. And a projection optical system for projecting and displaying the image light combined by the color separation / combination optical system. Between the system and the color separation / combination optical system, the illumination light from the illumination optical system is transmitted to the color separation / combination optical system, and the image light from the color separation / combination optical system has a reflectance close to 100%. A light guide element for guiding light rays along a center line of an illumination light flux in the illumination optical system, the color separation / synthesis optical system, and the projection optical system. Trace line at When the reference axis of the entire system, the reference axis in the color separation and synthesis optical system and the reference axis in the projection optical system are respectively inclined with respect to the normal line of the display surface of the image display element, and the color A projection type image display device, characterized in that a polarizing element for transmitting only a specific polarized component light is provided between the disassembling and combining optical system and the image display element. 7. The first light guide element allows the illumination light to enter and reflects the image light with a reflectance close to about 100%.
Surface, a second surface that emits the illumination light incident from the first surface toward the color separation / combination optical system and the image light from the color separation / combination optical system is incident, and the second surface.
7. The projection type image according to claim 5, further comprising: a third surface that emits the image light that is incident from the surface and reflected by the first surface toward the projection optical system. Display device. 8. The incident angle of the illumination light incident on the second surface of the light guide element and the incident angle of the image light incident on the second surface are different from each other. The projection type image display device described in. 9. The light guide element is formed in a wedge shape, and an auxiliary optical element for refracting and transmitting image light emitted from the light guide element is provided between the light guide element and the projection optical system.
7. The projection type image display device according to claim 2, wherein the light guide element is arranged with an air gap. 10. The light guide element is formed in a wedge shape, and an auxiliary optical element for refracting and transmitting illumination light from the illumination optical system is provided between the light guide element and the illumination system. 7. The projection type image display device according to claim 2, wherein the light guide element is arranged with an air gap. 11. The projection type display according to claim 1, wherein the image display element modulates and reflects incident illumination light and emits it as image light. Image display device. 12. The projection optical system is a decentered optical system having at least one rotationally asymmetric surface or a plurality of optical elements having mutually different rotational symmetry axes. 6. The projection type image display device according to any one of 6. 13. A projection type image display device according to claim 1, and an image information supply device for supplying image information to be displayed on the projection type image display device. An image display system characterized by the following.