JP2002122812A - Illumination optical device and projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a simple and inexpensive illumination optical device capable of making all the luminous flux emitted from a light source incident on a liquid crystal panel. SOLUTION: For example, P polarized light out of the non-polarized luminous flux emitted from the light source 1 is transmitted through a PBS 7 and made incident on the liquid crystal panel 8 as it is, and for example, S polarized light out of the above-mentioned luminous flux is reflected on the PBS 7, a reflection mirror 9 and the PBS 7 in this order and made incident on a polarized light conversion element 4. The element 4 is constituted to have two-layer structure consisting of a 1/4 wavelength plate array 41 and a reflection mirror array 4b, so that the S polarized light is changed to the P polarized light by rotatory polarization by the array 4a and reflection by the array 4b and made incident on the panel 8 through the PBS 7 again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for an illumination optical device most suitable for application to, for example, a liquid crystal projector for projecting a full-color image or the like onto a screen or the like, and a projection display device using the illumination optical device. Belongs to the field.

[0002]

2. Description of the Related Art Conventionally, a projection display device using a liquid crystal panel as a spatial light modulator has been called a liquid crystal projector device. The liquid crystal panel itself in this liquid crystal projector device does not have a light emitting function, and in combination with an illumination optical device, the light emitted from the light source is condensed by a condensing lens or the like to illuminate the liquid crystal panel and be applied to the liquid crystal panel The input light is phase-modulated (light-modulated) in accordance with the video signal to be transmitted. And
By projecting an image or the like phase-modulated by a liquid crystal panel on a projection display unit such as a screen by a projection lens, a small and efficient projector device is realized.

Some liquid crystal materials used in liquid crystal panels have a property (flash property) that changes the polarization of incident light in accordance with an applied electric field (applied voltage). In many cases, phase modulation for rotating polarized light is performed by utilizing the method. Therefore, the light beam incident on the liquid crystal panel needs to be linearly polarized light in one direction.

On the other hand, many illumination optical devices of a liquid crystal projector use a light source that emits unpolarized light.
Excluding lasers, few light sources emit light with a high degree of polarization, and their light output is also small. In general, as a light source used in a liquid crystal projector device, a combination of a discharge lamp using an arc discharge and a reflection condensing mirror serving as a reflector is often used. There are various types of discharge lamps, such as mercury lamps and cannon lamps, depending on the type of gas to be sealed. In any case, since the light emitted from the light source is non-polarized, there is no light on the incident side of the liquid crystal panel. A polarizing plate for polarizing the polarized light into linearly polarized light in one direction must be provided.

[0005] Since the light emitted from the liquid crystal panel undergoes phase modulation in which the polarization is rotated according to the video signal applied to the liquid crystal panel, it is necessary to arrange an analyzer on the emission side of the liquid crystal panel. .

FIG. 19 is a schematic diagram showing a basic configuration of a conventional transmission type liquid crystal projector device which satisfies the above-mentioned conditions, and includes a discharge lamp 31a and a reflection condenser mirror 31b. The configured light source 31 and the condenser lens 3
2, an incident side polarizing plate 33, a transmission type liquid crystal panel 34,
It comprises an output-side polarizing plate 35 as an analyzer and a projection lens 36.

Then, a non-polarized light beam, for example, P-polarized light + S-polarized light emitted from the light source 31 is condensed by the condenser lens 42 and is polarized by the incident-side polarizing plate 43 into one linearly polarized light, for example, P-polarized light. To enter the transmissive liquid crystal panel 34, where the other linearly polarized light, for example, S
Polarized light is discarded outside. And the transmission type liquid crystal panel 3
One linearly polarized light, for example, P-polarized light, which is phase-modulated by the video signal applied to the light source 4, is output, and the emitted light is analyzed by the emission-side polarizing plate 35, and the projection display unit such as a screen is projected by the projection lens 36. The image is projected and displayed by projecting the image on the 37.

However, in this transmissive liquid crystal projector, only half of the unpolarized light emitted from the light source 31, for example, P-polarized light, is transmitted to the transmissive liquid crystal panel 34, and the other half is S-polarized light. In the method in which the light is discarded outside at the incident side polarizing plate 33, only half of the total amount of light emitted from the light source 31 can be used, so that a screen such as an image projected on the projection display unit 37 becomes dark. However, there is a problem that a high-brightness liquid crystal projector cannot be realized.

FIG. 20 is a schematic diagram for explaining the basic structure of a conventional reflection type liquid crystal projector device. The light source 41 includes a discharge lamp 41a and a reflection condenser 41b. A condensing lens 42, a polarization beam splitter (hereinafter simply referred to as PBS) 43, which is a polarization splitting / combining element that also serves as a polarizer and an analyzer, a reflective liquid crystal panel 44, and a projection lens 45. It is configured.

Then, a non-polarized light beam, for example, P-polarized light + S-polarized light emitted from the light source 41 is condensed by the condenser lens 42 and is incident on the PBS 43. The polarized light is polarized into, for example, P-polarized light (or S-polarized light). For example, only the P-polarized light is transmitted and incident on the reflection type liquid crystal panel 44. Reflected and discarded outside. Then, one-way linearly polarized light phase-modulated to, for example, S-polarized light by the video signal applied to the reflective liquid crystal panel 44 is emitted from the incident surface, re-enters the PBS 43, is reflected by the polarization separation / combination surface 43a, and is projected. It is configured such that a full-color image or the like is projected and displayed by being incident on the lens 36 and projected on the projection display unit 46 such as a screen.

However, also in this reflection type liquid crystal projector, half of the unpolarized light beam emitted from the light source 41, for example, only P-polarized light, is reflected by the reflection type liquid crystal panel 44, and the other half. For example, PB
Because it is a method of discarding outside in S43 part,
Again, since only half of the total amount of light emitted from the light source 41 can be used, a screen such as an image projected on the projection display unit 46 becomes dark, and a high-brightness liquid crystal projector cannot be realized. There was a problem.

[0012]

Therefore, to date,
A polarization conversion technique has been proposed for converting substantially all of the unpolarized light emitted from the light source into linearly polarized light. For example, the polarization conversion technique disclosed in Japanese Patent Application Laid-Open No. H8-304739 is a combination of an integrator optical system, a polarization separation prism array, and a 位相 retardation plate, and is constituted by a plurality of lenses. The condensing lens array, which is also called a multi-lens array, has a high affinity with the integrator optical system and can perform efficient polarization conversion.

However, the polarized light separating prism array is composed of a polarized beam splitter composed of a prismatic prism composite having a polarized light separating film inside, and a reflective prism composed of a rectangular prism shaped prism composite having a reflecting film inside. A pair of mirrors must be used as a basic structural unit to form a composite structure in which a plurality of pairs are arranged in a plane. Therefore,
In particular, this polarization separation prism array is not suitable for mass production because it is very difficult to produce a polarization separation film in each prism of the square prism composite in this polarization separation prism array. This polarization separation prism array is very expensive. And
There is a problem that the cost of the entire projection display device is increased by the polarization separation prism array.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is an illumination device capable of illuminating an illuminated portion with all unpolarized light beams by simple and inexpensive means. It is an object to provide an optical device and a projection display device.

[0015]

According to the present invention, there is provided an illumination optical apparatus comprising: a light source; and a first multi-lens array for dividing light emitted from the light source into a plurality of light spots by a plurality of lenses. A second multi-lens array for condensing a plurality of light spots divided by the first multi-lens array by a plurality of lenses, and a plurality of spots condensed by a plurality of lenses of the second multi-lens array, respectively. A condensing lens that collects and emits light so as to overlap each other, and a polarized light that separates outgoing light from the condensing lens into two different linearly polarized lights, transmits one linearly polarized light, and reflects the other linearly polarized light By separating the other linearly polarized light reflected by the polarization separation / combination element and re-entering the polarization separation / combination element, the other linearly polarized light is reflected by the polarization separation / combination element. A reflecting mirror that reflects and emits light toward the second multi-lens array, and the other linearly polarized light that is arranged parallel to a position near the focal point of the first multi-lens array and reflected and emitted by the reflecting mirror and the polarization splitting / combining element A polarization conversion element composed of a polarization rotation element and a polarization reflection element that converts the other linearly polarized light into the same linearly polarized light as one of the linearly polarized lights by rotation and reflection, and re-enters and transmits the polarization separation / combination element. And an illuminated part which is illuminated by all the light beams of one linearly polarized light and the other linearly polarized light transmitted through the polarization separation / combination element.

In the illumination optical device of the present invention configured as described above, the non-polarized light emitted from the light source is converted into a light beam in which a plurality of light spots are superimposed on each other by the first and second multi-lens arrays and the condenser lens. When the light is condensed and illuminated to the illuminated part through the polarization separation / combination element, the polarization separation / combination element transmits only one linearly polarized light of the unpolarized light flux and emits the light to the illuminated part. The other linearly polarized light of the unpolarized light beam reflected by the separation / combination element is reflected by a reflecting mirror, re-enters and reflects on the polarization separation / combination element, and the other reflected linearly polarized light is reflected by a second light. The light enters a polarization conversion element arranged near the focal point of one multi-lens array. Then, the other linearly polarized light passes through the polarization rotation element of the polarization conversion element, is reflected by the polarization reflection element, and is again passed through the polarization rotation element, so that the other linearly polarized light is rotated twice in a reciprocating manner. By passing through the element, the other linearly polarized light is converted into the same polarized light as one of the linearly polarized lights. Then, the other linearly polarized light, which has been converted into the same linearly polarized light as the one linearly polarized light, is again incident on and transmitted through the polarization separation / combination element, and the other linearly polarized light is also incident on the illuminated portion. is there.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an illumination optical device and a projection display device to which the present invention is applied will be described below with reference to FIGS.

First Embodiment of Illumination Optical Device First, a first embodiment of an illumination optical device will be described with reference to FIGS. 1 to 4. As shown in FIG. Lamp 1a and reflective condenser mirror (also referred to as condenser reflector)
1b, first and second multi-lens arrays (hereinafter, simply referred to as MLA) 2, 3, a polarization conversion element 4, first and second condenser lenses 5, 6, A polarization beam splitter (hereinafter simply referred to as a PB
S), a liquid crystal panel 8 as an illuminated part,
It is composed of a simple and inexpensive optical element with the reflecting mirror 9.

Then, the first and second light beams are placed on the optical axis F1 of the light source 1.
The MLAs 2 and 3, the polarization conversion element 4, the first and second condenser lenses 5 and 6, the PBS 7 and the liquid crystal panel 8 are respectively disposed at predetermined intervals and at right angles to the optical axis F 1. I have. The polarization separation / combination film 7a of the PBS 7 is inclined at 45 ° with respect to the optical axis F1. The reflecting mirror 9 is arranged at a predetermined angle on the reflecting optical axis F2 of the polarization separation / combination film 7a perpendicular to the optical axis F1.

The first and second MLAs 2 and 3 correspond to FIG.
As shown in FIG. 2, a plurality of lenses 2 each having a curvature on one or both sides of a lens substrate made of a transparent glass plate or the like.
a, 3a are integrally formed in a matrix or the like, and a plurality of lenses 3a of a second MLA 3 are arranged near the focal positions of the plurality of lenses 2a of the first MLA 2, respectively. Then, a non-polarized light beam having luminance unevenness, which is emitted by the discharge lamp 1a of the light source 1 and reflected and condensed by the reflection / condensing mirror 1b, is incident on the plurality of lenses 2a of the first MLA 2, thereby generating the plurality of lenses. Lens 2
a, the light spots are divided into a plurality of light spots parallel to the optical axis F1, and the plurality of light spots are condensed substantially in the center of the corresponding plurality of lenses 3a of the second MLA 3 in parallel with the optical axis F1 to form a first condensed light. The light is incident on the lens 5 in parallel with the optical axis F1.
The plurality of light spots are condensed by the first and second condensing lenses 5 and 6 so as to be superimposed on each other, and are emitted, so that a substantially uniform light flux without uneven brightness is formed. .

Next, the polarization conversion element 4 has a two-layer structure in which a quarter-wave plate array 4a, which is a polarization rotation element, and a reflection mirror array 4b, which is a polarization reflection element, are bonded by bonding or the like. ing. And this polarization conversion element 4 is also the second ML
Similar to A3, it is arranged near the focal point of the plurality of lenses 2a of the first MLA 2. However, the second MLA 3 and the polarization conversion element 4 are arranged in parallel on the optical axis F1 in a close state. The polarization conversion element 4 has the first MLA
A plurality of light transmitting portions 4c for transmitting a plurality of light spots formed by the two plurality of lenses 2a are formed. In the first embodiment of the illumination optical device, as shown in FIG.
As shown in FIG. 4, a plurality of light transmitting parts 4c of the polarization conversion element 4 are arranged in a parallel manner between the LA 3 and the first condenser lens 5, and a quarter wavelength plate array 4a and a reflecting mirror array 4b. And a plurality of slit-shaped (or matrix-shaped) openings penetrating through.

Here, the illumination operation of the liquid crystal panel 8 according to the first embodiment of the illumination optical device will be described with reference to FIG.
First, as shown in FIG. 1A, the light emitted from the light source 1 is non-polarized light (also referred to as non-polarized light), for example, a P-polarized light + S-polarized light beam. The luminous flux of the P-polarized light + S-polarized light is first and second MLA.
The light passes through a plurality of light transmitting portions 4 c of the polarization conversion element 4, and is condensed by the first and second condenser lenses 5 and 6, and is incident on the PBS 7.

Then, the P-polarized light + S incident on the PBS 7
The polarized light flux is separated by the polarization separation / combination film 7a into P-polarized light, which is one linearly polarized light, and S-polarized light, which is the other linearly polarized light.
For example, P-polarized light, which is one of the linearly polarized lights, passes through the polarization separation / combination film 7a and enters the liquid crystal panel 8.

The other linearly polarized light, for example, S-polarized light, is reflected at right angles by the polarized light separating / combining film 7a and is incident on the reflecting mirror 9, then is reflected by the reflecting mirror 9 and again reflected by P-polarized light.
The light enters the polarization separation / combination film 7 a of the BS 7. At this time, since the reflecting mirror 9 is inclined at a predetermined angle with respect to the reflecting optical axis F2, the incident angle of the S-polarized light with respect to the reflecting mirror 9 and the angle of the reflecting angle with respect to the optical axis F2 are different. 9
The S-polarized light reflected at is given a predetermined angle and
Is reflected again by the polarization separation / combination film 7a, is given a predetermined angle, and is incident on the second condenser lens 6.

The S-polarized light having the predetermined angle is parallelized to the optical axis F1 by the second condenser lens 6 and the first condenser lens 5 to the corresponding quarter-wave plate array 4a of the polarization conversion element 4. And is transmitted through the quarter-wave plate array 4a (first transmission). At this time, this 1
The retardation axis of the wave plate is set in the 波長 wavelength plate array 4a so that the incident S-polarized light is converted into １ ／ circularly polarized light, and the 透過 wavelength plate array 4a is transmitted through the １ ／ wavelength plate array 4a for the first time. S
The polarized light is converted into quarter-polarized light, and is incident on the reflecting mirror array 4b perpendicular to the optical axis F1 at right angles.

Then, as shown in FIG. 1B, the 1/4 circularly polarized light of the S-polarized light is again incident on the 1/4 wavelength plate array 4a in parallel with the optical axis F1. The light is transmitted through the plate array 4a (the second transmission), where
The 偏光 -circularly polarized light of S-polarized light is further converted to １ ／ -circularly polarized light and further converted to P-polarized light. That is, the S-polarized light is transmitted through the quarter-wave plate array 4a twice in a reciprocating manner, and is converted from the S-polarized light into the P-polarized light.

In this way, the P-polarized light converted from S-polarized light to P-polarized light by the polarization conversion element 4 and emitted in parallel with the optical axis F1 is again transferred to the PBS 7 by the first and second condenser lenses 5, 6. The incident P-polarized light is transmitted through the polarization separation / combination film 7a as it is, and
Will be incident. Therefore, all of the unpolarized P-polarized light and S-polarized light emitted from the light source 1 are transmitted to the liquid crystal panel 8.
And the incident surface 8a of the liquid crystal panel 8 can be uniformly illuminated with high luminance.

According to the first embodiment of the illumination optical device, the structure disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-304739 is complicated, and the polarization conversion technique (polarization) which is difficult to manufacture. (Optical element for conversion), it is not necessary to use a quarter-wave plate array 4a and a reflector array 4b.
Is easy to manufacture because of the simple structure
The objective can be achieved only by installing the polarization conversion element 4 which is an optical element having a layer structure and the reflection mirror 9. Further, the PBS 7 also serves as the incident-side polarizing plate of the conventional transmission type liquid crystal projector described with reference to FIG. 19, and the number of components is greatly reduced.

[Second Embodiment of Illumination Optical Apparatus] Next, referring to FIGS. 5A and 5B, a second embodiment of the illumination optical apparatus will be described.
In this case, the reflecting mirror 9 described with reference to FIGS. 1 to 4 in the first embodiment of the illumination optical device is arranged at right angles to the optical axis F2.
When the reflecting mirror 9 is disposed at right angles to the optical axis F2, the light is emitted from the light source 1 and the first and second multi-lens arrays 2, 3, as described in the first embodiment. ,
The non-polarized light (P) passing through the plurality of light transmitting portions 4c of the polarization conversion element 4 and the first and second condenser lenses 5 and entering the PBS 7
Of the outgoing light of (polarized light + S-polarized light), the incident angle and the reflection angle of the S-polarized light, which is reflected by the polarization separation / combination film 7a of the PBS 7 and enters the reflecting mirror 9, with respect to the reflecting mirror 9 are relative to the reflected optical axis F2. And become symmetrical.

That is, as shown in FIG. 5A, the S-polarized light of the non-polarized light beam incident on the PBS 7 at a position above the optical axis F1 of the light source 1 is converted into the polarized light separating / combining film 7a and the reflecting mirror 9A.
When the light is reflected again by the polarization splitting / combining film 7a of the PBS 7 and is emitted toward the second condenser lens 6, the １ ／ wavelength of the polarization conversion element 4 is symmetrically positioned below the optical axis F1. The light is incident on the plate array 7a. Similarly, as shown in FIG. 5B, S-polarized light of non-polarized light that has entered the PBS 7 below the optical axis F1 of the light source 1 is reflected by the polarization separation / combination film 7a and the reflecting mirror 9. After that, when the light is reflected again by the polarization separation / combination film 7a of the PBS 7 and is emitted toward the second condenser lens 6, the light enters the quarter-wave plate array 4a of the polarization conversion element 4 at a position symmetrical above the optical axis F1. Will be done.

Therefore, when the reflecting mirror 9 is arranged at right angles to the reflecting optical axis F2, for example,
The second multi-lens arrays 2 and 3 are deflected downward with respect to the optical axis F1, while the polarization conversion element 4 is deflected upward with respect to the optical axis F1. If arranged in an asymmetric state, the S-polarized light incident on the PBS 7 from the upper position and the lower position of the optical axis F1 will be shifted to the quarter wavelength plate array 4a at the lower position and the upper position of the optical axis F1, respectively.
And can accurately reach the reflecting mirror array 4b.

[Third Embodiment of Illumination Optical Apparatus] Next, a third embodiment of the illumination optical apparatus will be described with reference to FIG. 6. In this case, the first embodiment described with reference to FIGS. 14 explains the degree of freedom of the arrangement position of the polarization conversion element 4 in the illumination optical device according to the embodiment. That is, the quarter-wave plate array 4a and the reflecting mirror array 4b of the polarization conversion element 4 may be arranged at a position near the focal point of the first MLA 2. In the first embodiment, the polarization conversion element 4 is connected to the second MLA 2.
Although arranged on the emission side of the MLA 3, it may be arranged on the incidence side of the second MLA 3 as shown in the third embodiment. However, in this case, a plurality of light spots formed by the plurality of lenses 2a of the first MLA 2 are focused on a plurality of opposed lenses 3a of the second MLA 3 through the plurality of light transmitting portions 4c of the polarization conversion element 4. So
It is desirable that the polarization conversion element 4 and the second MLA 3 are arranged close to each other so that the plurality of lenses 3a of the second MLA 3 are inserted into the plurality of light transmitting portions 4c.

[Fourth Embodiment of Illumination Optical Apparatus] Next, a fourth embodiment of the illumination optical apparatus will be described with reference to FIGS. 7 and 8. In this case, the polarization conversion element 4 is replaced by the second MLA 3. Alternatively, it is integrated with the first condenser lens 5. That is, in the embodiment shown in FIG. 7, the reflecting mirror array 4b of the polarization conversion element 4 is integrally formed on the emission surface of the second MLA 3 by vacuum deposition of aluminum or the like, and a quarter of the reflecting mirror array 4b is formed on the reflecting mirror array 4b. The wave plate array 4a is integrated by bonding or the like. The polarization conversion element 4 that has been processed separately from the second MLA 3 may be integrated on the output surface or the input surface of the second MLA 3 by bonding or the like. In the embodiment shown in FIG. 8, the polarization conversion element 4 is integrated on the incident surface of the first condenser lens 5 by bonding or the like.

[Fifth Embodiment of Illumination Optical Device] Next, a fifth embodiment of the illumination optical device will be described with reference to FIG. 9. In this case, a different structure of the polarization conversion element 4 is shown. For example, a reflector array 4b and a quarter-wave plate array 4a are sequentially formed on a transparent substrate 4d such as a transparent glass plate, and are installed by using the transparent substrate 4d. Position adjustment at the time can be easily performed.

"Sixth Embodiment of Illumination Optical Device" Next, a sixth embodiment of the illumination optical device will be described with reference to FIGS. 10 and 11. In this case, light transmission of the polarization conversion element 4 will be described. It shows a variant of the part 4c. That is, the plurality of light spots formed by the plurality of lenses 2a of the first MLA 2 in the first embodiment of the illumination optical device described in FIGS. 1 to 4 may have a complicated distribution, and FIG. It shows an example of the distribution of the light spot SL.

On the other hand, as described with reference to FIGS. 1 and 2, the polarization conversion element 4 disposed near the focal point of the first MLA 2
Are formed with a plurality of light transmitting portions 4c for transmitting a light spot SL formed by the plurality of lenses 2a of the first MLA 2. Therefore, as shown in FIG. 11, a plurality of light transmitting portions 4 formed on the polarization conversion element 4 are formed.
By making the distribution of c correspond to the distribution of the plurality of light spots SL formed by the first MLA 2 shown in FIG.
Highly efficient polarization conversion can be performed.

That is, as described with reference to FIGS. 1A and 1B, P-polarized light + S-polarized light which is emitted light from the light source 1 and formed into a plurality of light spots by the plurality of lenses 2a of the first MLA 2. 11 passes through the light transmitting portion 4c having the distribution shown in FIG. 11 of the polarization conversion element 4 and is incident on the PBS 7, and the S-polarized light reflected by the reflection mirror 9 is again a quarter-wave plate array 4a of the polarization conversion element 4. And the reflected light is reflected by the reflecting mirror array 4b to perform polarization conversion.
Since the wave plate array 4a and the reflecting mirror array 4b are present in all of the portions (the portions shown by cross-hatching in FIG. 12) 4e other than the plurality of light transmitting portions 4c shown in FIG. Light loss during polarization conversion (S-polarized light passes through the light transmitting portion 4c to the first MLA 2 side and escapes,
(Reflection by the reflector array 4b) can be minimized, and highly efficient polarization conversion can be performed.

[Seventh Embodiment of Illumination Optical Apparatus] Next, a seventh embodiment of the illumination optical apparatus will be described with reference to FIGS. FIG. 1 illustrates the degree of freedom of arrangement and the like.
2, the PBS 7 is disposed between the first condenser lens 5 and the second condenser lens 6 on the optical axis F1, and the P-polarized light and the S-polarized light transmitted through the PBS 7 are transmitted to the second condenser lens. 6, the light can be condensed on the liquid crystal panel 8.
Further, as shown in FIG. 13, a third condenser lens 10 is disposed between the PBS 7 and the reflecting mirror 9, and is reflected by the polarization separating / combining film 7 a of the PBS 7 and then reflected by the reflecting mirror 9. The third condensing lens 10 may be configured so that the polarized light reaches the desired position of the quarter-wave plate array 4a of the polarization conversion element 4 accurately. Also, as shown in FIG.
The third condenser lens 10 is a lens system including a concave lens, for example,
It may be constituted by a combination lens 11 in which a concave lens 11a and a convex lens 11b are combined.

In the illumination optical system using the first and second MLAs 2 and 3, one of the first and second condenser lenses 5 and 6 can be omitted depending on design conditions.

The polarization separation / synthesis element is not necessarily a PBS.
It does not need to be 7, and for example, a reflective polarizing plate or the like may be used. This reflective polarizer transmits P-polarized light and reflects S-polarized light, similar to PBS7. Specific products include DBEF manufactured by Sumitomo 3M Limited.

"Eighth Embodiment of Illumination Optical Device" Next, an eighth embodiment of the illumination optical device will be described with reference to FIG. 15. In this case, the polarization separation plate 12 is used as a polarization separation / synthesis element. Cholesteric liquid crystal is used for the polarization separation plate 12, and transmits one circularly polarized light, for example, clockwise circularly polarized light, and reflects the other circularly polarized light, for example, counterclockwise circularly polarized light. It performs separation and synthesis of circularly polarized light. The PBS 7 in the first embodiment of the illumination optical device described with reference to FIGS. 1 to 4 is replaced by a polarization separation plate 12, which is inclined at 45 ° with respect to the optical axis F1. Has been arranged. On the optical axis F1, a quarter-wave plate 13 is disposed between the polarization separation plate 12 and the liquid crystal panel 8 at a right angle to the optical axis F1.

According to the eighth embodiment of the illumination optical device, the unpolarized (right-handed circularly polarized light + left-handed circularly polarized light) beam emitted from the light source 1 is divided into the first and second multi-lens arrays. The light passes through a plurality of light transmitting portions 4 c of the polarization conversion element 4, is condensed by the first and second condensing lenses 5 and 6, and is incident on the polarization splitting plate 12. Then, for example, clockwise circularly polarized light (or counterclockwise circularly polarized light), which is one of the non-polarized light incident on the polarization separation plate 12, transmits through the polarization separation plate 12 and then becomes a １ ／ wavelength plate 13. Is transmitted to the liquid crystal panel 8 after being polarized to one linearly polarized light, for example, P-polarized light (or S-polarized light).

On the other hand, left-handed circularly polarized light (or right-handed circularly polarized light), which is the other circularly polarized light in the non-polarized light incident on the polarized light separating plate 12, is reflected by the polarized light separating plate 12 at a right angle, and is reflected by a reflecting mirror. 9, the polarized light separating plate 1
2, the light is reflected again by the polarization separation plate 12, passes through the second condenser lens 6 and the first condenser lens 5, and travels to the polarization conversion element 4. Then, as in the first embodiment described with reference to FIGS.
After being transmitted through the four-wavelength plate array 4a and reflected by the reflecting mirror array 4b, the light is transmitted through the quarter-wavelength plate array 4a again, and passes through the quarter-wavelength plate array 4a twice in a reciprocating manner. As a result, the left-handed circularly polarized light is converted into right-handed circularly polarized light. Then, the converted right-handed circularly polarized light passes through the first and second condenser lenses 5 and 6, and is again polarized-light separating plate 1
2 and is transmitted through the polarization separation plate 12, and
The light is polarized by the wave plate 12 into one-way linearly polarized light, for example, P-polarized light (or S-polarized light), and is incident on the liquid crystal panel 8. Therefore, all the unpolarized right-handed circularly polarized light and left-handed circularly polarized light emitted from the light source 1 are incident on the liquid crystal panel 8 to uniformly illuminate the incident surface 8a of the liquid crystal panel 8 with high luminance. be able to.

"Ninth Embodiment of Illumination Optical Device" Next, a ninth embodiment of the illumination optical device will be described with reference to FIG. 16. In this case, the illumination optical device described with reference to FIGS. The arrangement of the liquid crystal panel 8 and the reflecting mirror 9 in the device is interchanged. Since the liquid crystal panel 8 and the reflecting mirror 9 are optically conjugated, no optical problem occurs even if they are interchanged. do not do. However, in this case, the liquid crystal panel 8 is disposed at a right angle to the reflection optical axis F2, and the reflection mirror 9 is disposed at a predetermined angle to the optical axis F1.

According to the ninth embodiment of the illumination optical device, the non-polarized light (P-polarized light +
(S-polarized light) is transmitted to the first and second multi-lens arrays 2 and 3
Pass through the plurality of light transmitting portions 4c of the polarization conversion element 4 and are condensed by the first and second condenser lenses 5 and 6, and P
It is incident on BS7. Then, in this case, the S-polarized light is reflected at right angles by the polarization separation / combination film 7 a of the PBS 7 and enters the liquid crystal panel 8. In this case, the P-polarized light passes through the polarization separation / combination film 7a of the PBS 7 and
Is incident on. The P-polarized light is reflected by the reflecting mirror 9 so that the incident angle and the outgoing angle with respect to the optical axis F1 are different from each other, and passes through the polarization separation / combination film 7a of the PBS 7, and the second condenser lens 6 and the first condenser lens 5 Through the polarization conversion element 4
Go to Then, as in the first embodiment described with reference to FIGS. 1 to 4, the P-polarized light passes through the quarter-wave plate array 4a and is reflected by the reflecting mirror array 4b, and then returns to the quarter-wavelength. The P-polarized light is converted into S-polarized light by passing through the quarter-wave plate array 4a twice in a reciprocating manner so as to transmit through the plate array 4a. The S-polarized light converted from the P-polarized light into the S-polarized light is converted into the first and second condenser lenses 5,
6, the light is again incident on the PBS 7, is reflected at right angles by the polarization separation / combination film 7 a of the PBS 7, and is incident on the liquid crystal panel 8. Therefore, all the unpolarized P-polarized light and S-polarized light emitted from the light source 1 are incident on the liquid crystal panel 8, and the incident surface of the liquid crystal panel 8 can be uniformly illuminated with high luminance.

However, in the ninth embodiment, FIG.
If the configuration in which the plurality of light transmitting portions 4c of the polarization conversion element 4 according to the second embodiment described in (A) and (B) are arranged in a vertically asymmetric state with respect to the optical axis F1 is adopted, the reflecting mirror 9 can be used.
Can be arranged at right angles to the optical axis F1.

"Embodiment of Transmissive Liquid Crystal Projector" Next, referring to FIG. 17, an embodiment of a transmissive liquid crystal projector which is an example of the projection display apparatus will be described. The liquid crystal panel 8 according to the first to ninth embodiments is configured as a transmission type liquid crystal panel 8A, and a projection lens 14 is arranged on the emission side of the transmission type liquid crystal panel 8A. Note that FIG.
FIG. 7 illustrates the illumination optical device according to the first embodiment shown in FIG.

According to this transmission type liquid crystal projector, as described above, all the unpolarized light beams emitted from the light source 1, for example, P-polarized light + S-polarized light (or right-handed polarized light + left-handed polarized light) are emitted. The light can be incident on the incident surface 8a of the transmissive liquid crystal panel 8A to illuminate the incident surface 8 with high luminance. The transmissive liquid crystal panel 8A is provided with an analyzer, and all the light beams incident on the incident surface 8a of the transmissive liquid crystal panel 8A are modulated according to the video signal applied to the transmissive liquid crystal panel 8A. Exit surface 8b
The projection lens 14 projects an image of high brightness and uniform brightness on a projection display unit 15 such as a screen.

"Embodiment of Reflective Liquid Crystal Projector" Next, an embodiment of a reflective liquid crystal projector as another example of the projection display apparatus will be described with reference to FIG. First to optical devices
The liquid crystal panel 8 in the ninth embodiment is configured as a reflective liquid crystal panel 8B, and the projection lens 14 is a reflection mirror on the extension of the reflection optical axis F2 with the PBS 7 (or the polarization separation plate 12) serving as a polarization conversion element interposed therebetween. 9 is arranged on the opposite side. Note that FIG. 18 illustrates the first embodiment shown in FIG. 2 as an illumination optical device.

According to the reflection type liquid crystal projector, as described above, all the unpolarized light beams emitted from the light source 1, for example, P-polarized light + S-polarized light (or clockwise polarized light + counterclockwise polarized light) are emitted. The light can be incident on the incident surface 8a of the reflective liquid crystal panel 8B to illuminate the incident surface 8a with high luminance. Then, all the light beams incident on the incident surface 8a of the reflective liquid crystal panel 8B are modulated according to the video signal applied to the reflective liquid crystal panel 8B, internally reflected, and emitted from the same incident surface 8b. After being reflected by the polarization separation / combination film 4a of the PBS 7 on the side opposite to the reflection mirror 9, an image of high brightness and uniform brightness is projected on the projection display unit 15 such as a screen by the projection lens.

[Embodiment of Three-Plate Liquid Crystal Projector] In FIGS. 17 and 18 described above, a single-panel liquid crystal projector using one transmissive liquid crystal panel 8A or reflective liquid crystal panel 8B has been described. Using three liquid crystal panels 8A and three reflective liquid crystal panels 8B,
The present invention can also be applied to a three-panel type liquid crystal projector that projects a full-color image on a projection display unit 15 such as a screen by a projection lens 14. In this case, for example, a color separation element is arranged on the emission side or the like of the first condenser lens 5 shown in FIGS. 17 and 18, and the unpolarized light flux from the light source 1 is converted into red R, green G, and blue B light. In order to separate the light into three colors, and to perform the above-described polarization conversion on the light beams of the three colors R, G, and B, three optical systems are provided between the second condenser lens 6 and the projection lens 14. What is necessary is just to arrange a system. Note that the color separation element may be arranged on the emission side of the polarization separation / combination element such as PBS7.

[Application of Illumination Optical Apparatus to Other Apparatus] FIG. 1
The first to ninth embodiments of the illumination optical device described with reference to FIG. 16 to FIG. 16 have been described as the illumination optical devices of the transmission type and reflection type liquid crystal projector devices described with reference to FIG. 17 and FIG. The apparatus can be widely applied as an illumination optical apparatus for various purposes using polarized light, such as a semiconductor exposure apparatus, and a high efficiency can be obtained by applying the illumination optical apparatus of the present invention to a semiconductor exposure apparatus. Semiconductor exposure becomes possible.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made based on the technical concept of the present invention.

[0054]

According to the illumination optical apparatus of the present invention, the unpolarized light emitted from the light source is condensed by the first and second multi-lens arrays and the condenser lens into a light beam in which a plurality of light spots are superimposed on each other. When illuminating the illuminated section through the polarization separation / combination element, the polarization separation / combination element transmits only one linearly polarized light of the unpolarized light flux and emits the light to the illuminated section, and the polarization separation / combination element uses the same. The other linearly polarized light of the reflected unpolarized light flux is reflected by a reflecting mirror, re-enters and reflects on the polarization splitting / combining element, and the other linearly polarized light is reflected by the first multi-lens array. Is incident on the polarization conversion element arranged at the position near the focal point. And
The other linearly polarized light passes through the polarization rotation element of the polarization conversion element, is reflected by the polarization reflection element, and is again passed through the polarization rotation element. By passing the light, the other linearly polarized light is converted into the same polarized light as one of the linearly polarized lights. Then, the other linearly polarized light converted into the same linearly polarized light as the one linearly polarized light is again incident on and transmitted through the polarization separation / combination element, so that the other linearly polarized light is also incident on the illuminated portion. All of the unpolarized light flux emitted from the light source is incident on the illuminated portion, and the illuminated portion can be uniformly illuminated with high luminance. Nevertheless, since the polarization conversion element has a simple structure consisting of a two-layer structure of a polarization rotation element and a polarization reflection element, it can be made of a simple and inexpensive optical element that is easy to manufacture, so that low-cost illumination optics can be used. The device can be realized.

According to the projection display apparatus of the present invention, the unpolarized light emitted from the light source is condensed into a light beam in which a plurality of light spots are superimposed on each other by the first and second multi-lens arrays and the condensing lens, and polarization separation is performed. When the light enters the spatial light modulator through the combining device, the polarized light separating / combining device transmits only one linearly polarized light of the unpolarized light beam and emits it to the spatial light modulator, and is reflected by the polarized light separating / combining device. The other linearly polarized light of the non-polarized light beam thus reflected is reflected by the reflecting mirror, re-enters and reflects on the polarization splitting / combining element, and the other reflected linearly polarized light is reflected by the first multi-lens array. The light enters the polarization conversion element arranged near the focal point. Then, the other linearly polarized light passes through the polarization rotation element of the polarization conversion element, is reflected by the polarization reflection element, and is again passed through the polarization rotation element, so that the other linearly polarized light is rotated twice in a reciprocating manner. By passing through the element, the other linearly polarized light is converted into the same polarized light as one of the linearly polarized lights. Then, the other linearly polarized light, which has been converted into the same linearly polarized light as the one linearly polarized light, is again incident on the polarization separation / combination element and transmitted therethrough, and the other linearly polarized light is also incident on the spatial light modulation element. All of the unpolarized light beams emitted from the light source are incident on the spatial light modulator, all of the light beams are modulated by a video signal applied to the spatial light modulator, and a projection lens unit such as a screen is formed by a projection lens. Therefore, it is possible to realize a high-performance projection display device capable of projecting an image with high brightness and uniform brightness. Nevertheless, the polarization conversion element has a simple structure having a two-layer structure of a polarization rotation element and a polarization reflection element, and can be constituted by a simple and inexpensive optical element that is easy to manufacture. The device can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a state of a light beam incident on a liquid crystal panel by combining P-polarized light and S-polarized light in a first embodiment of an illumination optical device of a liquid crystal projector device to which the present invention is applied.

FIG. 2 is a schematic diagram illustrating a configuration of the illumination optical device according to the first embodiment.

FIG. 3 is a three-sided view showing a front surface, a top surface, and side surfaces for explaining first and second multi-lenses of the illumination optical device.

FIG. 4 is a perspective view illustrating a polarization conversion element of the illumination optical device according to the first embodiment.

FIG. 5 is a schematic diagram illustrating a configuration and a light beam of a second embodiment of the illumination optical device according to the first embodiment.

FIG. 6 is a schematic diagram illustrating a configuration of a third embodiment of the illumination optical device according to the third embodiment.

FIG. 7 is a schematic diagram illustrating a first example of the configuration of the illumination optical device according to the fourth embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a second example of the configuration of the illumination optical device according to the fourth embodiment.

FIG. 9 is a schematic diagram illustrating a configuration of a fifth embodiment of the illumination optical device according to the embodiment.

FIG. 10 is a diagram illustrating a distribution of light spots formed by a first multi-lens array in a sixth embodiment of the illumination optical device.

FIG. 11 is a diagram illustrating a distribution of light transmitting portions of a polarization conversion element in the illumination optical device according to the sixth embodiment.

FIG. 12 is a schematic diagram illustrating a first example of the configuration of the illumination optical device according to the seventh embodiment.

FIG. 13 is a diagram illustrating a second example of the configuration of the illumination optical device according to the seventh embodiment.

FIG. 14 is a diagram illustrating a second example of the configuration of the illumination optical device according to the seventh embodiment of the present invention.

FIG. 15 is a schematic diagram illustrating the configuration and light rays of an illumination optical device according to an eighth embodiment of the present invention.

FIG. 16 is a schematic diagram illustrating a configuration of a ninth embodiment of the above illumination optical device.

FIG. 17 is a schematic diagram illustrating a configuration of an embodiment of a transmissive liquid crystal projector device to which the present invention has been applied.

FIG. 18 is a schematic diagram illustrating a configuration of a reflection type liquid crystal projector device to which the invention is applied.

FIG. 19 is a schematic diagram illustrating a configuration of a conventional transmissive liquid crystal projector device.

FIG. 20 is a schematic diagram illustrating a configuration of a conventional reflective liquid crystal projector device.

[Explanation of symbols]

1 is a light source, 2 is a first multi-lens array, 3 is a second multi-lens array, 4 is a polarization conversion element, 4a is a quarter-wave plate array which is a polarization rotation element of a polarization conversion element, and 4b is a polarization conversion element. 5 is a first condenser lens, 6 is a second condenser lens, 8 is a liquid crystal panel which is a spatial light modulator, 8A is a transmissive liquid crystal panel, 8B is a reflective liquid crystal panel, 9 is a reflecting mirror, 10 is a third condenser lens, 11 is a combination lens, 12 is a polarization splitter, and 13 is 1
The 波長 wavelength plate and 14 are projection lenses.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 21/00 G03B 21/00 E 5C060 21/14 21/14 A H04N 5/74 H04N 5/74 K 9 / 31 9/31 CF term (reference) 2H042 CA10 CA14 CA17 2H049 BA05 BA07 BA43 BB01 BB63 BC22 2H052 BA02 BA03 BA06 BA14 2H099 AA12 BA09 CA02 CA07 DA05 5C058 AA06 AB03 AB06 BA05 BA23 BA29 5C060 BA07 BB13 HC09 HC01 HC05 GB01

Claims (12)

[Claims] A light source; a first multi-lens array for dividing light emitted from the light source into a plurality of light spots by a plurality of lenses; and a plurality of light spots divided by the first multi-lens array. A second multi-lens array that collects light by a lens, a condensing lens that collects and emits a plurality of spots collected by the plurality of lenses of the second multi-lens array so as to overlap each other, A polarized light separating / combining element that separates outgoing light from the condenser lens into two different linear polarized lights, transmits one linear polarized light, and reflects the other linear polarized light, and the other reflected by the polarized light separating / combining element. By reflecting the linearly polarized light and re-entering the polarization separation / combination element, the other linearly polarized light is reflected by the polarization separation / combination element and reflected by the second multi-lens array. A reflecting mirror that emits light to the side A, and a rotation and reflection of the other linearly polarized light that is arranged in parallel at a position near the focal point of the first multi-lens array and is reflected and emitted by the reflecting mirror and the polarization splitting / combining element. A polarization conversion element composed of a polarization rotation element and a polarization reflection element for converting the other linearly polarized light into the same linearly polarized light as one of the linearly polarized light, and re-entering and transmitting the polarization separation / combination element; An illumination optical device, comprising: an illuminated part that is illuminated by all of the one linearly polarized light and the other linearly polarized light transmitted through the separation / combination element. 2. The polarization conversion element according to claim 1, wherein the polarization rotation element is one.
The illumination optical device according to claim 1, wherein the illumination optical device is configured by a / 4 wavelength plate array, and the polarization reflection element is configured by a reflection mirror array. 3. The polarization conversion element according to claim 1, wherein the polarization rotation element is one.
The illumination optical device according to claim 1, wherein the illumination optical device has a polarization rotation function substantially equal to that of the quarter-wave plate array and is made of a liquid crystal material. 4. The illumination optical device according to claim 1, wherein said polarization separation / combination element is constituted by a polarization beam splitter. 5. The illumination optical device according to claim 1, wherein said polarization separation / combination element is constituted by a reflection type polarizing plate. 6. The device according to claim 1, wherein the polarization separation / combination element is made of a cholesteric liquid crystal material, and is an element that separates and combines polarization in accordance with the direction of rotation of circularly polarized incident light. Illumination optics. 7. A plurality of light transmitting portions through which a plurality of light spots emitted from the second multi-lens array to the condenser lens are transmitted are formed in the polarization conversion element. Item 2. The illumination optical device according to item 1. 8. The illumination optical device according to claim 1, wherein said polarization conversion element is integrally connected to said second multi-lens array. 9. The illumination optical device according to claim 1, wherein the polarization conversion element is integrally connected to the condenser lens. 10. An illumination optical device, wherein said reflection mirror and said illuminated part have an optically conjugate relationship. 11. The illumination optical device according to claim 1, wherein the reflecting mirror is disposed at an angle or at a right angle to a reflection optical axis of the polarization beam splitter / combiner. 12. A light source, a first multi-lens array that divides outgoing light from the light source into a plurality of light spots by a plurality of lenses, and a plurality of light spots divided by the first multi-lens array. A second multi-lens array that collects light by a lens, a condensing lens that collects and emits a plurality of spots collected by the plurality of lenses of the second multi-lens array so as to overlap each other, A polarization separation / combination element that separates outgoing light from the condenser lens into two different linearly polarized lights, transmits one linearly polarized light, and reflects the other linearly polarized light, and the other reflected by the polarization separation / combination element By reflecting linearly polarized light and re-entering the polarization splitting / combining element, the other linearly polarized light is reflected by the polarization splitting / combining element to reflect the second multi-lens. A reflecting mirror that emits toward the ray side; and a polarization and reflection of the other linearly polarized light that is arranged parallel to a position near the focal point of the first multi-lens array and is reflected and emitted by the reflecting mirror and the polarization splitting / combining element. A polarization conversion element composed of a polarization rotation element and a polarization reflection element, which converts the other linear polarized light into the same linear polarized light as the one linear polarized light, and re-enters and transmits the polarization separation / combination element; A space that is illuminated by all the light beams of the one linearly polarized light and the other linearly polarized light transmitted through the separation / combination element, and modulates and emits all of the one linearly polarized light and the other linearly polarized light by applying a video signal. A projection display device comprising: a light modulation element; and a projection lens that projects light emitted from the spatial light modulation element.