JPH07199187A - Projection device - Google Patents

Abstract

PURPOSE:To provide a projection device capable of observing a bright projected image by efficiently condensing a luminous flux emitted from a light source on the pupil surface of a projection lens and increasing projection efficiency. CONSTITUTION:The luminous flux from a light source means 1 is separated into two luminous fluxes of polarized light component by a polarized light separating means 4. After the polarizing direction of either of two separated luminous fluxes of polarized light component is aligned with t,hat of the other through a polarized light rotating means 5, two luminous fluxes are condensed by a condensing means 7 having two lens parts whose optical axes are different from each other and an image to be projected 8 is irradiated with the luminous flux through the condensing means and projected on a specified surface by a projection means 9. In such a case, respective elements are set so that the center axes of two separated luminous fluxes may be crossed near the pupil position of the projecting means on the image to be projected side in the condensing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection device, and more particularly, to effectively utilize a light beam from a light source means to efficiently illuminate a projected image on a liquid crystal panel or the like, and project the projected image on a screen surface by a projection lens. The present invention relates to a projection device that is suitable for a device such as a liquid crystal projector that is enlarged and projected.

[0002]

2. Description of the Related Art Conventionally, various projection apparatuses have been proposed in which a projection image original image displayed on a film, a liquid crystal light valve or the like is enlarged and projected on a screen surface.

FIG. 8 is a schematic view of a main part of an optical system of a conventional projection device. The figure shows a case where a transmissive liquid crystal panel (liquid crystal light valve) is used as a projected image to magnify and project the image.

In the figure, reference numeral 101 denotes a white light source, which is composed of, for example, a halogen lamp or a metal halide lamp. Reference numeral 102 denotes a reflector, which is composed of a reflecting surface such as a parabolic shape, and effectively guides the light flux emitted from the white light source 101 toward the liquid crystal panel 106. Reference numeral 103 denotes a filter (heat ray cut filter) that cuts off ultraviolet rays and infrared rays contained in white light. A condenser lens 104 condenses the illumination light flux reaching the liquid crystal light valve 106 on the pupil surface of the projection lens 108 on the panel side.

An image forming means 110 is a polarizing plate 105 for converting illumination light into linearly polarized light, a liquid crystal light valve 106 for modulating the linearly polarized light in accordance with an image signal, and the modulated linearly polarized light. It is composed of a polarizing plate 107 or the like that selects and transmits only the transmission component. A projection lens (projection lens) 108 magnifies and projects the image formed on the liquid crystal light valve 106 on a screen (not shown) at a predetermined magnification.

In the figure, of the luminous flux emitted from the light source means 101, the reflected light reflected by the reflector 102 and the direct light not passing through the reflector 102 pass through the filter 103 and are converted into a substantially parallel luminous flux by the condenser lens 104. Is converted into linearly polarized light through the polarizing plate 105, and the converted linearly polarized light is used for the liquid crystal light valve 106.
Is illuminating. Then, the image information of the liquid crystal light valve 106 passing through the polarizing plate 107 is enlarged and projected on a screen (not shown) by a projection lens 108.

In the conventional projection apparatus shown above, only the luminous flux of the linearly polarized light component in one direction of the luminous flux emitted from the white light source 101 is used for illumination, so that the illumination efficiency is low and 50% at the maximum. There is only utilization efficiency.

In view of the above, a conventional projection apparatus that improves the above-mentioned drawbacks and improves the utilization efficiency of illumination light is disclosed in, for example, Japanese Patent Laid-Open No. 61-90.
It is proposed in Japanese Patent No. 584. FIG. 9 is a schematic view of a main part of an optical system of a projection device proposed in the publication, and FIG. 10 is a schematic view of a main part schematically showing an optical path of an illumination light flux of the projection device proposed in the publication. . 9 and 10, the same elements as those shown in FIG. 8 are designated by the same reference numerals.

In FIGS. 9 and 10, reference numeral 120 denotes a polarization beam splitter, which splits a light beam L2 of a P polarization component and a light beam L1 of an S polarization component. Reference numeral 121 is a total reflection prism, 122 is a half-wave plate, 123 is a wedge prism, and 124 is a chamfered lens (condenser lens).
Is.

In FIG. 9 and FIG. 10, the light flux from the white light source 101 that has passed through the filter 103 is incident on the polarization beam splitter 120, and the light flux of the P-polarized component is generated at the separation surface (bonding surface) 120b on which the dielectric thin film is vapor-deposited. (P polarized light) L
2 and an S-polarized light flux (S-polarized light) L1. Of the separated light beams, the light beam L2 of the P-polarized component that has passed through the separation surface 120b is emitted from the emission surface 120c, and the light beam L1 of the S-polarized component that is reflected by the separation surface 120b is incident on the total reflection prism 121 and is reflected on the reflection surface. The light path L2 of the P-polarized component is reflected from the exit surface 121b by switching the optical path reflected by 121a.
Is ejected in the same direction as. The light flux L1 of the S-polarized component is 1 /
The polarization direction is rotated by 90 degrees by the two-wave plate 122 and is converted into a light flux of the same linear polarization component as the light flux L2 of the P polarization component.

Then, two P's are formed by the wedge prism 123.
Kamaboko lens 1 that combines the light fluxes L1 and L2 of the polarization components
The liquid crystal light valve 106 is illuminated through 24.
Then, the image information of the liquid crystal light valve 106 is enlarged and projected by a projection lens 108 onto a screen (not shown) surface.

[0012]

In the conventional projection device shown in FIG. 9 (FIG. 10), the polarization beam splitter 1 is used.
Since the two light beams L1 and L2 separated by 20 are combined into one light beam using the wedge prism 123,
The optical path L (space) required for the synthesis is required, and there is a problem that the entire optical system becomes large.

Further, in this type of projection apparatus (illumination system), the illumination efficiency is highest when the image of the light source is formed on the pupil plane of the projection lens. In the above projection apparatus, as shown in FIG. 10, two light beams apparently appear in the liquid crystal light valve 106.
Since the optical system is a biaxial optical system that intersects on the surface, two light sources separate and form an image at the position of the pupil 108a of the projection lens 108.

Therefore, in such a projection apparatus, a projection lens having an extremely large pupil is required, which is not practical, resulting in vignetting of the light source by the projection lens, and rather the utilization efficiency of the illumination light flux from the light source. There was a problem that it lowered.

Besides, the optical paths of the light beams emitted from the polarization beam splitter are arranged to be parallel to each other, and after partially illuminating the liquid crystal light valve, they are condensed on the pupil plane of the projection lens by a condenser lens. Such a projection device has been proposed.

However, in the above-mentioned projection device, since the light beam from the light source reflected by the reflector is not necessarily parallel light, the light beam spreads widely on the pupil plane of the projection lens, and the light source by the projection lens is used similarly to the above-mentioned conventional projection device. Vignetting occurs, which rather reduces the utilization efficiency of the illumination light flux from the light source.

In the present invention, the light beam from the light source means is separated into two by the polarization separating means, and the polarization direction of one of the separated light rays is made to coincide with the polarization direction of the other light beam by the polarization rotating means.
The projected object is irradiated with the two separated light beams, the projected object is projected by the projection lens, and the central axes of the two light beams are near the pupil on the image forming means (liquid crystal panel) side of the projection lens. By appropriately configuring each element so that the light source images are formed so as to overlap each other on the pupil plane of the projection lens, effective utilization of the illumination light flux from the light source means and good projection can be achieved. The purpose is to provide a possible projection device.

[0018]

In the projection apparatus of the present invention, a light beam from a light source unit is separated into two light beams having two polarization components by a polarization separating unit, and one of the two light beams having the two polarization components is separated. After making the polarization direction of the other light beam coincide with the polarization direction of the other light beam through the polarization rotation means, the two light beams are condensed by the light condensing means having two lens portions whose optical axes are different from each other,
When the projection image is irradiated with the light flux that has passed through the light converging means and the projection image is projected onto the predetermined surface by the projection means, the light converging means has the central axes of the two separated light fluxes of the projection means. The feature is that each element is set so as to intersect near the pupil position on the projected image side.

Particularly, the optical axes of the two lens portions constituting the condensing means are symmetrical with respect to the optical axis of the projecting means and are parallel to each other.

[0020]

EXAMPLE 1 FIG. 1 is a schematic view of a main part of an optical system of Example 1 of the present invention. FIG. 2 is a schematic view of a main part schematically showing the optical path of the illumination light in the first embodiment.

In the figure, 1 is a white light source (light source means),
Made of metal halide lamp. Reference numeral 2 denotes a reflector, which is composed of a reflecting surface such as a parabolic shape, and effectively guides the light flux emitted from the white light source 1 toward a liquid crystal panel (liquid crystal light valve) 8 described later. Reference numeral 3 is a filter that blocks ultraviolet rays and infrared rays contained in white light.

Reference numeral 4 denotes a polarized beam separating element as a polarized light separating means, which is formed by laminating a plurality of thin glass plates (optical elements) so as to be substantially parallel to each other with a longer interval than a wavelength. The white light transmitted through the filter 3 is separated into a P-polarized component light flux (P-polarized light) L2 and an S-polarized light flux (S-polarized light) L1. In this embodiment, S-polarized light L1 of the light beams separated by the polarization separation means 4 is obtained by reflection, and P-polarized light L2 is obtained by transmission.

Numeral 5 is a half-wave plate as a polarization rotating means, which converts the azimuth angle of the light beam (P-polarized light) L2 of one polarization component separated by the polarization separating means 4 by 90 degrees to obtain another polarization. The polarization direction of the component light flux (S-polarized light) L1 is matched. 6 is a reflection mirror as a reflection means, which is 1/2
The optical path of the light beam (S-polarized light) whose azimuth angle is rotated by the wave plate 5 is bent to the side of the light collecting means 7 described later.

Denoted at 7 is a condenser means (condenser lens) having two lens portions arranged so that the optical axes d and e are different from each other. The condensing means 7 is arranged in the vicinity of the liquid crystal panel 8 to be described later, and the S separated by the polarization separating means 4 is arranged.
It is arranged in the vicinity of the position where the central axes (optical axes of the reflector 2) a and b of the two light fluxes of the polarized light component L1 and the P polarized light component L2 intersect. The optical axes d and e of the two lens portions 7a and 7b are arranged symmetrically with respect to the optical axis c of the projection lens 8.

In the present embodiment, the reflectors 2, so that the central axes of the two light beams (S-polarized light L1 and P-polarized light L2) separated by the polarization separation means 4 intersect in the vicinity of the position of the panel side pupil 9a of the projection lens 9. Each element such as the polarized light separating means 4, the reflecting mirror 6 and the condensing means 7 is arranged. Further, the condensing means 7 in this embodiment has two illumination light fluxes L reaching the liquid crystal panel 8.
1, L2 are the pupils 9a on the panel side on the optical axis e of the projection lens 9.
It is focused on the position.

Reference numeral 8 denotes a TN type liquid crystal panel (liquid crystal light valve) for displaying an image as a projected image of one element of the image forming means. Polarization filters (not shown) whose polarization directions are orthogonal to each other are provided in front of and behind the liquid crystal panel 8, and the polarization filter on the incident side of the liquid crystal panel 8 has an optical function as a polarizer for completely illuminating the luminous flux. The exit-side polarization filter has an optical function as an analyzer that cuts and modulates a light beam whose polarization direction does not rotate in the liquid crystal panel 8. An image forming unit is composed of these elements.

Reference numeral 9 denotes a projection lens (projection lens) as a projection means, which enlarges and projects the image (original image of the projected image) formed on the liquid crystal panel 8 on the screen 10 which is the projection surface at a predetermined magnification. There is.

In the present embodiment, of the light flux (white light) emitted from the white light source 1, the light flux emitted to the front (on the side of the filter 3) is the same, and the light flux emitted to the rear is the liquid crystal using the reflector 2. The light is effectively guided to the panel 8 side. At this time, since the white light source 1 is not a complete point light source, the emitted light flux is not a parallel light flux, but a light flux having a certain spread. This emitted light beam is separated by the polarization separation means 4 into a light beam (P-polarized light) L2 having a substantially P-polarized component and a light beam (S-polarized light) L1 having a substantially S-polarized component. Then, the light flux L1 of the S-polarized component reflected by the polarized light separating means 4 is condensed by one lens portion 7a constituting the condensing means 7 and illuminates the liquid crystal panel 8.

On the other hand, the other P transmitted through the polarization separation means 4
The light flux L2 of the polarization component has its polarization direction rotated by 90 degrees by the half-wave plate 5 so as to match the polarization direction of the light flux L1 of the S polarization component, and the other lens that constitutes the condensing means 7 via the reflection mirror 6. The light is condensed by the portion 7b to illuminate the liquid crystal panel 8.

The luminous flux (image light) emitted from the liquid crystal panel 8 is 9 times larger than the incident luminous flux projected on the liquid crystal panel 8.
Since the polarization direction is rotated by 0 degree, it is emitted as a light flux of a P polarization component. Then, the image formed by the liquid crystal panel 8 is enlarged and projected on the surface of the screen 10 by the projection lens 9 at a predetermined magnification.

As described above, in this embodiment, the polarization splitting means 4, the mirror 6, and the condensing means (condenser lens) 7 including the two lens portions 7a and 7b having different optical axes d and e are used. Then, the liquid crystal panel can be efficiently illuminated with the light flux emitted from the white light source 1, and thus the projection efficiency can be increased. For example, a bright projected image is observed even on a large screen.

In this embodiment, as the polarized light separating means, a polarized light beam separating element in which a plurality of optical elements made of a glass plate or the like whose surface has been subjected to surface treatment such as vapor deposition is laminated is used. A polarization beam splitter composed of prisms or a polarization beam separation element having a plurality of glass plates arranged without vapor deposition may be used.

The condensing means (condenser lens) 7 composed of the two lens portions 7a and 7b may be formed, for example, by cutting and adhering the two lenses, or integrally so as to have two curvatures. It may be molded into. Further, the two lens portions may be molded so as to have different refracting powers depending on the distances of the respective optical paths to the light source. Further, even if each of the two lens portions is composed of a Fresnel lens, it can be applied similarly to the above-mentioned embodiment.

In this embodiment, the azimuth angle of the light flux of the P-polarized component is rotationally converted by the 1/2 wavelength plate to illuminate the liquid crystal panel as the combined light of the S-polarized component. Alternatively, the liquid crystal panel may be illuminated with the combined light of the P-polarized component.

FIG. 3 is a schematic view of the essential parts of an optical system according to a second embodiment of the present invention. FIG. 4 is a schematic view of a main part schematically showing the optical path of illumination light in the second embodiment. In FIGS. 3 and 4, the same elements as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In FIGS. 3 and 4, reference numeral 34 denotes a polarization beam splitter composed of a prism as a polarization separation means, which separates the light beam from the white light source 1 incident from the incident surface 34a of the polarization beam splitter 34 (bonding surface). 34
In b, the light beam of P polarization component (P polarization) L2 and the light beam of S polarization component (S polarization) L1 are separated. In this embodiment, the S-polarized light L1 of the light beams separated by the polarization separation means 34 is obtained by reflection, and the P-polarized light L2 is obtained by transmission.

Reference numeral 33 denotes a total reflection prism, which is P-polarized light L2 transmitted through the separation surface 34b of the polarization beam splitter 34.
The reflecting surface 33b of the total reflection prism 33 collects
It is reflected to the 7 side.

Reference numeral 35 denotes a quarter-wave plate as a polarization rotating means, which rotatively converts the azimuth angle of the S-polarized light L1 reflected by the separation surface 34b of the polarization separating means 34 by 45 degrees, and again makes a quarter.
By passing through the wave plate 35, the polarization direction of the P-polarized light L2 is matched. Reference numeral 36 is a reflection mirror as a reflection means.

In this embodiment, the polarization beam splitter 34
Of the two light fluxes, the light flux L1 emitted from the exit surface 34c and the light flux L2 emitted from the exit surface 33b of the total reflection prism 33 (optical axis of the reflector 2 (target axis)).
It is set so that a and b are substantially parallel to each other.

Reference numeral 37 denotes a condenser means (condenser lens), which has two lens portions 37a and 37b and is arranged in the vicinity of the liquid crystal panel 8. Two lens parts 37
Reference numerals a and 37b are disposed in the vicinity of the position where the central axes a and b of the two light beams (S-polarized light and P-polarized light) L1 and L2 separated by the polarization separation means 34 intersect, in contrast to the optical axis c of the projection lens 9. is doing.

Reference numeral 38 denotes a two-divided wedge-type prism, which converts the emission directions of the two light beams L1 and L2 that have passed through the light converging means 37 to generate a pupil 9a on the panel side of the projection lens 9.
The light is guided to the vicinity.

In this embodiment, the light flux (white light) emitted from the white light source 1 is effectively guided to the liquid crystal panel 8 side using the reflector 2 and transmitted through the filter 3, and then the polarization separation means 34 is used. Incident on P
The light beam L2 of the polarization component and the light beam L1 of the S polarization component are separated. Of these, the light flux L2 of the P-polarized component that has passed through the separation surface 34b is reflected by the reflection surface 33a of the total reflection prism 33, exits from the exit surface 33b, and is guided to one lens portion 37a that constitutes the condensing means 7. There is.

On the other hand, the light flux L1 of the S-polarized component reflected by the separation surface 34b of the polarization separation means 34 has its polarization direction rotated by 45 degrees by the quarter-wave plate 35, and again passes through the reflection mirror 36 by the quarter-wave plate. 35, and the light beam L2 of the P-polarized component is made incident on the polarization splitting means 34 so as to match the polarization direction of the light beam L2. Then, the light is guided by the other lens 37b that passes through the separation surface 34b of the polarized light separating means 34, exits from the exit surface 34c, and constitutes the condensing means 37.

Two light fluxes L1 and L that have passed through the condensing means 37
Reference numeral 2 illuminates the liquid crystal panel 8 by changing the emission direction by a two-divided wedge prism 38. At this time, the light flux from the light source 1 is focused near the pupil 9a on the panel side 8 of the projection lens 9. Then, the image formed by the liquid crystal panel 8 is enlarged and projected on the surface of the screen 10 by the projection lens 9 at a predetermined magnification.

FIG. 5 is a schematic view of the essential parts of an optical system according to Example 3 of the present invention. FIG. 6 is a schematic view of a main part schematically showing the optical path of illumination light in the third embodiment. 5 and 6, the same elements as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In FIGS. 5 and 6, reference numeral 57 denotes a first condenser means (first condenser lens), and two lens portions 5 are provided.
7a and 57b, which are arranged near the liquid crystal panel 8. The two lens portions 57a and 57b are two light beams (S-polarized light and P-polarized light) L1 and L separated by the polarization separation means 4.
It is arranged symmetrically with respect to the optical axis c of the projection lens 9 in the vicinity of the position where the two central axes (optical axes of the reflector 2) a and b intersect.

Further, the first light collecting means 57 in the present embodiment.
Is configured so that the luminous flux incident on the liquid crystal panel 8 becomes almost a telecentric system. Reference numeral 58 denotes a second condenser means (second condenser lens), which condenses the luminous flux illuminating the liquid crystal panel 8 in the vicinity of the pupil 9a on the panel side 8 of the projection lens 9.

In the present embodiment, the light flux (white light) emitted from the white light source 1 is effectively guided to the liquid crystal panel side by using the reflector 2 and transmitted through the filter 3, and then the P light is separated by the polarization separating means 4. The light beam L2 of the polarization component and the light beam L1 of the S polarization component are separated. In this embodiment, S-polarized light L1 of the light beams separated by the polarization separation means 4 is obtained by reflection, and P-polarized light L2 is obtained by transmission.

The light beam L2 of the P-polarized component transmitted by the polarization separation means 4 is condensed by one lens portion 57b constituting the first condensing means 57 and illuminates the liquid crystal panel 8.

On the other hand, the light flux L1 of the S-polarized component reflected by the polarization splitting means 4 passes through the reflection mirror 6 and the half-wave plate 5
The polarization direction of the liquid crystal panel 8 is converted by 90 degrees to be matched with the polarization direction of the light flux L2 of the P-polarized component and condensed by the other lens portion 57a constituting the first condensing means 57.
Is illuminating.

After illuminating the liquid crystal panel 8, the two light beams L1 and L2 are condensed by the second condensing means 55 in the vicinity of the pupil 9a on the panel side 8 of the projection lens 9. Then, the image formed by the liquid crystal panel 8 is enlarged and projected on the surface of the screen 10 by the projection lens 9 at a predetermined magnification.

FIG. 7 is a schematic view of the essential parts of an optical system according to Example 4 of the present invention. In this embodiment, a case where a color image is projected using a plurality of liquid crystal panels is shown. In the figure, the same elements as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In the figure, reference numeral 70 denotes a polarization beam splitter, which reflects the light flux L1 of the S-polarized component of the light flux from the white light source 1 and guides it to the respective liquid crystal panels 78G, 78B, 78R, and the liquid crystal panels 78G, 78B, 78R. Then, the light beam L2 of the P-polarized component whose polarization direction is rotated by 90 degrees based on the image information is transmitted and guided to the projection lens 9. 71 is the first
The dichroic mirror has a spectral characteristic of reflecting the first color light (for example, G color light) and transmitting the second color light (for example, B color light) and the third color light (for example, R color light).
72 is a second dichroic mirror, which is used for the second color light (B
It has a spectral characteristic of transmitting color light) and reflecting the third color light (R color light).

78G is a liquid crystal panel (image) for the first color light, 78B is a liquid crystal panel (image) for the second color light, 78
R is a liquid crystal panel (image) for the third color light. 77G,
Reference numerals 77B and 77R are condenser means (condenser lenses) similar to those in the above-described first embodiment, and each liquid crystal panel 78.
It is arranged in the vicinity of G, 78B and 78R.

The two lens portions 77G1 and 77G2 (77B1 and 77B2, 77B1 and 77B2 of the light collecting means 77G, 77B and 77R, respectively).
77R1 and 77R2) are polarization beam splitters 7
It is arranged symmetrically with respect to the optical axis c of the projection lens 9 in the vicinity of the position where the central axes (optical axes of the reflector 2) a and b of the two light fluxes L1 and L2 from 0 intersect.

In this embodiment, the luminous flux emitted from the white light source 1 is reflected by the reflector 2 on the liquid crystal panel 78G,
The polarized light is effectively reflected toward the 78B and 78R sides and is separated by the polarization splitting means 4 into a light beam L1 of an S polarization component and a light beam L2 of a P polarization component. In the present embodiment, S-polarized light L1 of the light beams separated by the polarization separation means 4 is obtained by reflection, and P-polarized light L1 is obtained.
2 is obtained through transmission.

Then, the S-polarized light L1 reflected by the polarization separation means 4 is reflected by the polarization beam splitter 70, and the P-polarized light L2 transmitted through the polarization separation means 4 is rotated by 90 ° in the polarization direction by the ½ wavelength plate 5. Then, it is made to coincide with the polarization direction of the S-polarized light L1 and reflected by the polarization beam splitter 70 via the reflection mirror 6.

Then, with the first dichroic mirror 71, G
The color light is reflected, and the B color light and the R color light are transmitted. G
The color light is passed through the light collecting means 77G to the liquid crystal panel 7 for the G color light.
It is incident on 8G. Of the B-color light and the R-color light transmitted by the first dichroic mirror 71, the second dichroic mirror 72 reflects the R-color light, and the R-color light is passed through the condensing means 77R.
It is incident on the liquid crystal panel 78R for color light. The B-color light that has passed through the second dichroic mirror 72 is condensed by the light collecting means 77.
It is incident on the liquid crystal panel 78B for B color light through B.

Each liquid crystal panel 78G, 78B, 78
Each color light (light flux L2 of the P-polarized component) reflected by R based on the image information of each color light is combined using the second dichroic mirror 72 and the first dichroic mirror 71 to obtain a color image. Then, the colorized image is transmitted through the polarization beam splitter 70 and projected on the screen 10 surface by the projection lens 9 at a predetermined magnification.

Although the three-plate type projection device in this embodiment is constructed by using the reflection type liquid crystal panel as the image forming means, the same applies to the case where the transmission type liquid crystal panel is formed by expanding the optical path. can do.

[0061]

According to the present invention, of the two light beams separated by the polarization separating means as described above, the polarization direction of one light beam is made to coincide with the polarization direction of the other light beam by the polarization rotating means, and the light beams are separated. By configuring each element so that the central axes of the two light fluxes intersect near the pupil of the projection lens on the liquid crystal panel side, the illumination light flux from the light source means is efficiently condensed on the pupil surface of the projection lens. As a result, it is possible to achieve a projection apparatus that can increase the projection efficiency on the projection surface and can obtain a bright projection image even on a large screen.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of an optical system according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a main part schematically showing an optical path of illumination light in Example 1 of the present invention.

FIG. 3 is a schematic view of a main part of an optical system according to a second embodiment of the present invention.

FIG. 4 is a schematic view of a main part schematically showing an optical path of illumination light according to a second embodiment of the present invention.

FIG. 5 is a schematic view of a main part of an optical system according to a third embodiment of the present invention.

FIG. 6 is a schematic view of a main part schematically showing an optical path of illumination light according to a third embodiment of the present invention.

FIG. 7 is a schematic view of a main part of an optical system according to a fourth embodiment of the present invention.

FIG. 8 is a schematic view of a main part of an optical system of a conventional projection device.

FIG. 9 is a schematic view of a main part of an optical system of a conventional projection device.

FIG. 10 is a schematic view of a main part schematically showing an optical path of illumination light in a conventional projection device.

[Explanation of symbols]

 1 Light source means 2 Reflector 3 Filter 4,34 Polarization separating means 5 Polarization rotating means (1/2 wavelength plate) 6,36 Reflecting means 7,37,57,58 Condensing means 8 Projected image 9 Projecting means 10 Projected surface 33 Total Reflection Prism 35 1/4 Wave Plate 38 2-Division Wedge Prism 70 Polarizing Beam Splitter 71, 72 Dichroic Mirror 77G, 77B, 77R Condensing Means 78G, 78B, 78R Image Forming Means

Claims (2)

[Claims] 1. A light beam from a light source means is separated by a polarization separating means.
After splitting into two light fluxes of two polarization components, the polarization direction of one of the two light fluxes of the separated polarization components is made to match the polarization direction of the other light flux via the polarization rotation means, and then the two light fluxes are separated. When the light is condensed by a condensing unit having two lens units having different optical axes, the projected image is irradiated with the light beam passing through the condensing unit, and the projected image is projected on a predetermined surface by the projecting unit. The projection device is characterized in that each element of the light converging means is set such that the central axes of the two separated light beams intersect in the vicinity of the pupil position on the projected image side of the projection means. 2. The projection apparatus according to claim 1, wherein the optical axes of the two lens portions forming the light converging means are symmetrical with respect to the optical axis of the projecting means and parallel to each other. .