JP2003121794A - Illumination optical system and projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination optical system which has high light use efficiency and small illuminance unevenness and color unevenness by increasing the efficiency of superposition coupling of two pieces of projection luminous flux after polarization conversion in an illumination optical system including a polarized light converting element and to provide a projection type display device which uses the illumination optical system and has superior display image quality. SOLUTION: After random polarized light is converted into specific polarized light, the luminous flux is subdivided and respective pieces of the luminous flux are superposed and coupled, and guided to an illumination area, so the illumination optical system for light polarization can be realized, which has little divergence loss of light and also has small illuminance unevenness and color unevenness. The light projection type display device using the illumination optical system can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system and a projection type display device equipped with the illumination optical system.

[0002]

2. Description of the Related Art Improving the brightness of a display screen is one of the problems to be solved by a projection display device. Most light valves represented by liquid crystal light valves use polarized light to display images, so only one of the polarized components of the light from the light source is used for display, and therefore the light utilization efficiency is improved. It inherently has the drawback of being low.

In order to remedy this drawback, conventional methods, for example, Japanese Patent Laid-Open Nos. 63-121821 and 63-168622 have been used.
An illumination optical system using a polarization conversion element is proposed as shown in FIG. That is, it is intended to improve the brightness of the display image by converting the random polarized light from the light source into one kind of polarized light in advance and then making it enter the light valve.

Specifically, as shown in FIG. 7, a polarized light separating element 71 such as a polarizing beam splitter is used to convert random polarized light (natural light) 11 from a light source 10 into two linearly polarized light (P).
After splitting into polarized light 12 and S polarized light 13), the polarization plane of one polarized light (here, P polarized light 12) is rotated 90 degrees by the λ / 2 retardation plate 14 (referred to as S ′ polarized light 15 for convenience), and the other The polarization plane (here, S-polarized light 13) is made to coincide with the polarization plane, and one kind of polarized light (here, S-polarized light) is made as a whole, and the light valve 51 is illuminated. Reference numeral 62 is a general reflection mirror.

[0005]

In the above-mentioned conventional illumination optical system, the polarization separation efficiency in the polarization separation element differs between the two polarization components, and the amount of transmitted light varies depending on the presence or absence of the phase difference plate. Due to occurrences, it is necessary to superimpose S-polarized light and P-polarized light and guide them to the illumination area in actual use. However, since the light emitted from the light source used in a general projection display device has poor parallelism, it is necessary to simply adjust the direction of the light flux emitted from the polarization conversion element and guide it to the illumination area. Light diverges as it reaches the area,
Alternatively, since the illuminance distribution at the time of emission from the polarization conversion element is not preserved, the amount of light available in the illumination area decreases, and at the same time, large illuminance unevenness occurs. As a result, there is a problem that ideal illumination cannot be performed.

Therefore, the present invention solves the above problems, and an object thereof is to provide a superposition coupling efficiency of two outgoing light beams after polarization conversion in an illumination optical system having a polarization conversion element. It is intended to provide an illumination optical system having high light utilization efficiency and small unevenness in illuminance. Furthermore,
An object of the present invention is to provide a projection display device that uses an illumination optical system with high light utilization efficiency and small unevenness in illuminance and has excellent display image quality.

[0007]

In order to achieve the above object, the first illumination optical system of the present invention is a polarization separating element for separating random polarized light from a light source into two linear polarized light of P wave and S wave. And a polarization plane rotation element that rotates the polarization plane of one of the two polarized lights that has been separated and matches the polarization plane of the other linearly polarized light, that is, an illumination optical system having a polarization conversion element. And a prism type reflection mirror for bending one of the two polarized lights, which is reflected by the polarization splitting element, in the direction substantially the same as the outgoing direction of the other polarized light. A light transmission element for guiding the polarized light having undergone the polarization plane rotation action and the polarized light not receiving the polarized light emitted from the conversion element to the illumination area in a substantially superposed state is disposed between the polarization conversion element and the illumination area, The light transmitting element A first lens portion arranged at an incident portion of the light from the polarization conversion element, and a second lens portion arranged between the first lens portion and the illumination region, The lens unit of 1 includes a first lens plate in which a plurality of first unit lenses are arranged in a plane perpendicular to the optical axis of the light emitted from the polarization conversion element, and the second lens unit is A second lens plate in which a plurality of second unit lenses corresponding to each of the plurality of first unit lenses are arranged in a plane perpendicular to the optical axis of the light emitted from the polarization conversion element; A plurality of light source images formed by the first unit lens are formed near the center of each of the plurality of second unit lenses, and images near the plurality of first unit lenses are formed by the second lens unit. The first lens plate so as to form a superimposed image in the vicinity of the illumination area. Characterized in that a fine second lens plate.

The second illumination optical system of the present invention is a polarization splitting element for splitting random polarized light from a light source into two linear polarized light of P wave and S wave, and one of the separated two polarized light. A polarization plane rotating element for rotating the plane of polarization of the linearly polarized light of (1) to match the plane of polarization of the other linearly polarized light, the illumination optical system comprising: The polarized light reflected from the polarization conversion element is provided with a reflection mirror that bends the optical axis of the polarized light and emits the polarized light in substantially the same direction as the outgoing direction of the other polarized light. A light-transmitting element for guiding the polarized light that is not received to the illumination area in a substantially superposed state is disposed between the polarization-converting element and the illumination area, and the light-transmitting element is configured to transmit light from the polarization-converting element. Is located at the entrance A first lens unit and a second lens unit disposed between the first lens unit and the illumination area are provided, and the first lens unit is a light beam emitted from the polarization conversion element. A first lens plate having a plurality of first unit lenses arranged in a plane perpendicular to the axis, wherein the second lens portion is a plane perpendicular to the optical axis of the light emitted from the polarization conversion element; A second lens plate in which a plurality of second unit lenses corresponding to each of the plurality of first unit lenses are arranged, and a plurality of light source images formed by the plurality of first unit lenses are The first lens is formed in the vicinity of the center of each of the plurality of second unit lenses, and the images in the vicinity of the plurality of first unit lenses are superimposed and imaged in the vicinity of the illumination area by the second lens unit. A lens plate and the second lens plate are arranged, When the direction parallel to the plane including the separation direction in which the M-polarized light is separated into the P wave and the S wave is defined as the width direction, the dimension in the width direction of the first unit lens is the width of the polarization separation element. Direction dimension 1
It is characterized in that it is set to / n (n is a natural number) times.

In the second illumination optical system, the first illumination optical system
The dimension of the unit lens in the width direction may be set to 1 / n (n is a natural number) times the projected dimension in the width direction when the reflection mirror is projected in the optical axis direction of the illumination optical system. .

At least one of the first lens portion and the second lens portion may include one plano-convex lens and the lens plate. In addition, the above first to first aspects of the present invention
In the second illumination optical system, the polarization plane rotating element may be a λ / 2 retardation plate or a TN (twisted nematic) type liquid crystal element.

Further, the projection display device of the present invention comprises the above-mentioned illumination optical system, a light valve for modulating light from the illumination optical system by an image signal to form an image, and the formed image on the screen. And a projection optical system for projecting and displaying on.

Furthermore, another projection type display device of the present invention forms the image by illuminating the above-mentioned illumination optical system, a color light separating element for separating the light from the light source into three color lights, and modulating each color light by an image signal. It is characterized in that it includes three light valves, a color light combining element that combines three types of images of respective color lights into one, and a projection optical system that projects and displays the combined image on a screen.

[0013]

EXAMPLES The present invention will be described in detail below based on examples. However, the present invention is not limited to the following examples.

In the following embodiments, the case where the polarization plane of P-polarized light is rotated to be S-polarized will be described as an example.
Even when polarized, the features of the present invention are not lost. Further, in each embodiment, the same (including the same type) parts are given the same part number. (Embodiment 1) FIG. 1 is a schematic sectional view showing a first embodiment of the illumination optical system of the present invention. Random polarized light 11 emitted from the light source 10 is separated into two linear polarized lights of P polarized light 12 and S polarized light 13 by a polarization beam splitter 16 which is a polarization separating element. Since the polarization splitting power of the polarization beam splitter has an incident angle dependency, a light source provided with a lamp having a short arc length capable of emitting light with excellent parallelism is suitable. The separated P-polarized light is a polarization rotation element λ
By passing through the / 2 retardation plate 14, the polarization plane is rotated by 90 degrees and becomes S-polarized light. On the other hand, the S-polarized light 13 is emitted as S-polarized light as it is, only by bending the optical path by the prism type reflection mirror 17. Since the reflectance of the S-polarized light is higher than that of the P-polarized light in the reflection mirror made of the vapor-deposited film of aluminum, it is ideal that the optical path of the S-polarized light is bent by the reflection mirror. Although a prism type reflection mirror is used here, a general plane type reflection mirror may be used. With the above configuration, basically only S-polarized light is emitted from the polarization conversion element including the polarization separation element and the polarization plane rotation element.

Next, a light transmitting element composed of the first lens plate 21 and the second lens plate 22 is arranged between the polarization conversion element and the illumination area 23. The first lens plate and the second lens plate, as shown in FIG. 2 as an example of their external appearance, have a large number of unit lenses arranged in a plane perpendicular to the optical axis 26 of the illumination optical system. , The number of unit lenses forming the first lens plate 21 and the number of unit lenses forming the second lens plate 22 are equal, and the positional relationship of both unit lenses in the lens plate is also in a corresponding relationship. For example,
In FIG. 2, the unit lens 24 at the lower left of the first lens plate 21 has an optical correspondence with the unit lens 25 at the lower left of the second lens plate 22.

The optical correspondence between the unit lenses in the first and second lens plates will be described with reference to FIG. Here, for convenience, the unit lens forming the first lens plate is referred to as a lens A, and the unit lens forming the second lens plate is referred to as a lens B. The lens B is arranged between the lens A and the illumination area so that the image 35 near the lens A31 is transmitted to the illumination area 23 by the lens B33. In that case, the position of the lens B is determined by the ratio of the size of the opening cross section of the unit lens forming the lens A and the size of the illumination region, in other words, the magnification of the lens B.
Now, assuming that the distance between the lens A and the lens B is L1 and the distance between the lens B and the illumination area is L2, the size of the opening cross section of the unit lens forming the lens A: the size of the illumination area =
Since the relationship of L1: L2 is established, the position and the focal length of the lens B are determined based on this relationship. On the other hand, the lens A is arranged to enhance the light transmission efficiency of the lens B, and therefore, the light incident on the lens A should be collected in the central portion of the lens B (that is, near the center of the lens B by the lens A). The focal length of the lens A is determined so that a light source image is formed.

As described above, the image 35 in the vicinity of the lens A31 depends on the relationship between the focal lengths of the lens A and the lens B and the positional relationship between the lens A and the lens B and the illumination area.
Are transmitted to the illumination area 23 by the lens B33. At this time, since the focus of the lens A31 is near the center of the lens B33, the light incident near the center of the lens B is guided to the illumination region 23 as it is without being substantially refracted by the lens, and the lens B The light incident on the peripheral portion of is subjected to the refraction effect to change the optical path and is guided to the illumination area 23 as well, so that there is almost no light loss when the light is transmitted from the lens A to the illumination area. Therefore, if the size of the lens B is larger than the size of the light source image formed by the lens A, all the light passing through the lens A and entering the lens B is guided to the illumination area. That is, the light emitted from the polarization conversion element is transmitted to the illumination area with almost no light loss.

The relationship of transmitting the image in the vicinity of the lens A to the illumination area by the lens B also applies to the unit lenses (lens A32 and lens B34 in FIG. 3) deviated from the optical axis 26 of the illumination optical system. . In that case, either one of the lens A 32 and the lens B 34 or both of them must be a decentered lens (a lens in which the center of curvature forming the spherical shape of the lens is deviated from the lens center). In FIG. 3, the lens B34 deviated from the optical axis 26 of the illumination optical system, and in FIG. 1, all of the unit lenses forming the first lens plate 21 are decentered lenses. As shown in FIG. 1, by constructing the first lens plate with decentered unit lenses, there is an advantage that the size of the second lens plate can be reduced.

Regarding the shape of the lens A, since the image near the lens A is transmitted to the illumination area by the lens B, it is similar to the shape of the illumination area, and
It is necessary to consider that it is possible to form an array so that the light beam from the polarization conversion element can be effectively divided, and in this embodiment, the rectangular shape is used.

Returning to FIG. 1 again. All the unit lenses forming the first lens plate and all the unit lenses forming the second lens plate are optically in the one-to-one correspondence as described above. In FIG. 1, the light flux emitted from the polarization conversion element is divided into fine light fluxes by the unit lenses forming the first lens plate 21, and the same unit area as the illumination area by the corresponding unit lenses of the second lens plate 22. After being converted into a light beam having a size, the light beam is superposed and coupled to one illumination region and guided. As a result, even if the intensity of the light flux emitted from the polarization conversion element has a non-uniform distribution, the non-uniformity of the intensity distribution is averaged due to the subdivision and combination of the light flux, and the intensity unevenness and color in the illumination area are A good light distribution with little unevenness can be obtained.

Therefore, with the above construction, after the randomly polarized light from the light source is converted into one type of polarized light by the polarization conversion element, there is almost no light loss due to the light transmission element, and at the same time, uneven illuminance and Since the color unevenness is averaged and guided to the illumination area, it becomes an ideal illumination device that emits only one type of polarized light. The illumination optical system of the present invention is particularly effective when a light source with large illuminance unevenness or color unevenness is used. (Embodiment 2) FIG. 4 is a schematic sectional view showing a second embodiment of the illumination optical system of the present invention. The feature of this embodiment is that, unlike the case of the first embodiment described above, the second lens plate 22 includes a single large plano-convex lens 41 and a large number of unit lenses 4 having the same shape.
This is because it is a compound lens body composed of 2 and that the TN type liquid crystal element 44 is used as a polarization plane rotating element.

It is of course possible to form the second lens plate by only unit lenses of the decentering system, but in that case, it is necessary to manufacture many types of unit lenses having slightly different decentering amounts. On the other hand, when one large plano-convex lens 41 and the unit lens 42 are used in combination as in the present embodiment, the individual unit lenses can be made the same by optimizing the lens design. The complexity of time can be reduced. Of course, the above-mentioned lens configuration including one large plano-convex lens and a large number of unit lenses also applies to the first lens plate 21.

TN (Twisted Nematic)
The type liquid crystal element 44 is one in which nematic liquid crystal is homogeneously aligned while twisting nematic liquid crystal in the gap between the two transparent substrates (total twist angle is 90 degrees). When polarized light is incident in accordance with the alignment direction of the nematic liquid crystal, The polarization plane of light can be rotated according to the twisted state of liquid crystal molecules.
Therefore, this TN type liquid crystal element can be used as a λ / 2 retardation plate.

Furthermore, in the structure of this embodiment, the size of the second lens plate becomes large, so that the light rays that have passed through the second lens plate reach the illumination area at a larger angle than in the case of the first embodiment. Reach Therefore, in order to reduce the irradiation angle of the light applied to the illumination area to the same extent as in the case of the first embodiment (in other words, to increase the parallelism of the light), the irradiation area 23 as shown in FIG. Field lens 43 in front of
Should be installed. (Embodiment 3) FIG. 5 is a schematic sectional view showing a first embodiment of a projection type display device using the illumination optical system of the present invention. Λ / 2 phase difference plate 14 which is a polarization plane rotating element, polarization beam splitter 16 which is a polarization separating element, prism type reflection mirror 1
A polarization conversion element composed of 7 etc. and the first lens plate 2
The light transmitting element including the first and second lens plates 22 and the illumination optical system including both of them are functionally the same as those used in the illumination optical system of the first embodiment.

Randomly polarized light 11 from the light source 10 is converted into S-polarized light by the illumination optical system of the present invention, then superposed and combined near the field lens 43 and guided to the light valve 51 as illumination light. The field lens is the same as in the second embodiment.
As described above, it is installed in order to reduce the incident angle of light to the light valve and minimize the light loss due to the projection lens, but it is not always necessary depending on the characteristics of the projection lens. Here, only one liquid crystal light valve is used as a light valve, and two polarizing plates are attached to each of the front and back surfaces of the liquid crystal light valve. The transmission axis of the polarizing plate located on the light incident side is aligned with the polarization axis of S-polarized light, while the transmission axis of the polarizing plate located on the light exit side is orthogonal to the polarization axis of S-polarized light. The polarizing plate is arranged. In the case of this embodiment, since S-polarized light is incident on the liquid crystal light valve, a polarizing plate on the incident side is normally unnecessary, but it is used to further improve the polarization degree of polarized light incident on the liquid crystal light valve. There is. The liquid crystal light valve changes the amount of transmitted light according to an image signal and forms a display image by the difference in the amount of transmitted light, and generally uses a liquid crystal. However, in addition to the liquid crystal, a light valve can be used as long as it can form an image signal as a change in optical characteristics such as an electro-optic crystal. The display image formed by the light valve is enlarged and projected on the screen 53 surface by the projection lens 52.

Generally, in a projection display device, the display image on the screen surface becomes very dark due to the light loss in the projection lens and the light dispersion due to the enlarged projection. Therefore, in order to obtain a bright display image, it is essential to increase the amount of illumination light that illuminates the light valve as much as possible. Therefore, as shown in FIG. 5, by incorporating the illumination optical system according to the present invention into such a projection device, the illumination efficiency in the light valve can be increased, and as a result, a bright display image can be obtained. (Embodiment 4) FIG. 6 is a schematic sectional view showing a second embodiment of the projection type display apparatus using the illumination optical system of the present invention. The feature of this embodiment is that a color light separation element for separating light from a light source into three primary colors in the middle of an illumination optical system, three liquid crystal light valves, and three display images formed by the liquid crystal light valves are combined. The point is that it is possible to enlarge and project a colorized display image by using a color light combining element. However, the basic structure of the illumination optical system for illuminating the liquid crystal light valve is the same as that of the third embodiment.
Is the same as in.

A first unit composed of a decentered unit lens
A blue reflection dichroic mirror 61 that selectively reflects only blue light is placed after the lens plate 21 of (1) (the side opposite to the light source), and the two luminous fluxes bisected here are respectively reflected by the reflection mirror 62.
(However, the blue light is guided to the two second lens plates 22 by the double-sided reflection mirror 63). The light transmitted through the blue reflection dichroic mirror passes through the second lens plate 22 and then
The green reflection dichroic mirror 64 again divides the light into green light (reflected light) and red light (transmitted light), and the reflection mirror 62 (however, green light is a double-sided reflection mirror 63) bends the optical path, and then the field lens. After 43, the corresponding green light valve 65 and red light valve 66 are reached. On the other hand, blue light is reflected by two reflection mirrors 62.
After the optical path is bent by, it reaches the blue liquid crystal light valve 67 through the field lens 43. Two polarizing plates are attached to each of the three liquid crystal light valves, as shown in the third embodiment. In addition, the field lens 43
The purpose of use is the same as in Example 3.

The three display images (blue image, green image and red image) formed by the three liquid crystal light valves are color combining dichroic prisms 68 which are color light combining elements.
Thus, it is combined into a single colorized display image and enlarged and projected onto the screen 53 surface by the projection lens 52.

The projection type display device using three light valves has become the mainstream of the projection type display device because of its high resolution. The illumination optical system of the present invention can effectively exert its function even when incorporated in such a projection display device, and can be a powerful optical means for obtaining a bright display image.

[0030]

As described above, in the illumination optical system of the present invention, the polarization conversion element is combined with the light transmission element composed of two kinds of lens portions to convert the random polarization into the specific linear polarization, and after the conversion. It is possible to guide the two luminous fluxes to the illumination area while effectively superimposing and coupling them with almost no divergence loss of light, and as a result, it is possible to realize a bright illumination optical system that emits only polarized light with high efficiency. Particularly, the light flux emitted from the light flux conversion element is subdivided into a plurality of light fluxes,
Since the respective luminous fluxes are superposed and combined in the vicinity of the illumination area, the illuminance unevenness and the color unevenness (in the case where the light source has a low point light source property, this kind of unevenness is likely to occur) are averaged. As a result, there is a feature that illumination light with extremely small illuminance unevenness and color unevenness can be obtained. From the above, the illumination optical system of the present invention is particularly useful when a light source having a poor point light source property is used.

Further, by using the illumination optical system of the present invention, it is possible to realize a bright projection type display device with extremely little unevenness of illuminance and color unevenness, and the illumination optical system of the present invention is a high definition projection type. Effective for display devices.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a configuration of a first embodiment of an illumination optical system of the present invention.

FIG. 2 is a schematic external view of a first lens plate and a second lens plate used in Example 1.

FIG. 3 is a diagram for explaining an optical correspondence relationship between unit lenses in the illumination optical system of the present invention.

FIG. 4 is a schematic sectional view showing the configuration of a second embodiment of the illumination optical system of the present invention.

FIG. 5 is a schematic cross-sectional view showing a configuration of a first embodiment of a projection type liquid crystal display device using the illumination optical system of the present invention.

FIG. 6 is a schematic sectional view showing the configuration of a second embodiment of the projection type liquid crystal display device using the illumination optical system of the present invention.

FIG. 7 is a schematic sectional view showing an outline of a conventional illumination optical system using only polarization conversion elements.

[Explanation of symbols]

10 light sources 11 Random polarization (natural light) 12 P polarization 13 S polarization 14 λ / 2 retardation plate 15 S'polarized light (S polarized light converted from P polarized light) 16 Polarizing beam splitter 17 Prism type reflection mirror 21 First lens plate 22 Second lens plate 23 Illumination area 24 Unit lens forming the first lens plate 25 Unit lens forming the second lens plate 26 Optical axis of illumination optical system 31 lens A (on the optical axis of the illumination optical system) 32 lens A (not on the optical axis of the illumination optical system) 33 Lens B (located on the optical axis of the illumination optical system) 34 Lens B (not on the optical axis of the illumination optical system) 35 Image near lens A 36 Light incident near the center of lens B 37 Light incident near the periphery of lens B 41 Plano-convex lens 42 Unit lenses of the same shape 43 field lens 44 TN type liquid crystal element 51 light valve 52 Projection lens 53 screen 61 Blue reflective dichroic mirror 62 reflective mirror 63 Double-sided reflection mirror 64 green reflective dichroic mirror 65 Liquid crystal light valve for green 66 red liquid crystal light valve 67 Blue liquid crystal light valve Dichroic prism for 68-color light synthesis 71 Polarization separation element

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/1335 510 G02F 1/1335 510 1/13357 1/13357 F term (reference) 2H088 EA14 HA15 HA18 HA24 JA05 JA11 JA13 MA04 2H091 FA10Z FA11Z FA26X FA26Z FA27Z FA41Z LA18 MA07 2H099 AA12 BA09 CA02 CA08 DA09 2K103 AA01 AA05 AB05 AB06 BC15 BC17 BC26 BC27 CA17 CA40

Claims (6)

[Claims] 1. A polarization separating element for separating random polarized light from a light source into two linearly polarized light of P wave and S wave, and rotating the polarization plane of one of the separated two polarized light to rotate the other. An illumination optical system including a polarization conversion element having a polarization plane rotation element that matches a polarization plane of linearly polarized light, wherein one of the two polarizations reflected by the polarization separation element is A prism-type reflection mirror that bends the optical axis and emits light in the same direction as the emission direction of the other polarized light is provided. A light transmitting element for guiding the light to the illumination area in a state is arranged between the polarization converting element and the illumination area, and the light transmitting element is arranged at an incident portion of light from the polarization converting element. In front of the lens part A first lens unit and a second lens unit arranged between the illumination areas are provided, and the first lens unit is in a plane perpendicular to the optical axis of the light emitted from the polarization conversion element. A first lens plate in which a plurality of first unit lenses are respectively arranged, and the second lens portion is arranged in a plane perpendicular to the optical axis of the light emitted from the polarization conversion element. A second lens plate in which a plurality of second unit lenses corresponding to each of the unit lenses are arrayed, and a plurality of light source images formed by the plurality of first unit lenses are provided to each of the plurality of second unit lenses. The first lens plate and the second lens unit so as to form an image near the center of the plurality of first unit lenses in the vicinity of the illumination area by the second lens unit. An illumination optical system characterized in that a lens plate is arranged. 2. A polarization separating element for separating random polarized light from a light source into two linearly polarized light of P wave and S wave, and rotating the polarization plane of one of the separated two polarized light to rotate the other. An illumination optical system including a polarization conversion element having a polarization plane rotation element that matches a polarization plane of linearly polarized light, wherein one of the two polarizations reflected by the polarization separation element is A reflection mirror that bends the optical axis and emits light in the same direction as the emission direction of the other polarized light is provided, and the polarized light that is output from the polarization converting element and the polarized light that is not rotated is substantially overlapped. A light transmitting element for guiding the light to the illumination area is arranged between the polarization conversion element and the illumination area, and the light transmission element is arranged at an incident portion of light from the polarization conversion element. And the first A lens part and a second lens part arranged between the illumination regions, wherein the first lens part is provided with a plurality of first lens parts in a plane perpendicular to the optical axis of the light emitted from the polarization conversion element. A first lens plate in which one unit lens is arranged is provided, and the second lens unit includes each of the plurality of first unit lenses in a plane perpendicular to an optical axis of light emitted from the polarization conversion element. A second lens plate in which a plurality of second unit lenses corresponding to are arranged, and a plurality of light source images formed by the plurality of first unit lenses are provided near the center of each of the plurality of second unit lenses. The first lens plate and the second lens plate are arranged so that images formed near the plurality of first unit lenses are superimposed and imaged in the vicinity of the illumination area by the second lens unit. The randomly polarized light is divided into the P wave and the S wave. When the width direction is a direction parallel to a plane including the separation direction to be separated, the width dimension of the first unit lens is 1 / n (n is a natural number) of the width dimension of the polarization separation element. ) An illumination optical system characterized by being set to double. 3. The illumination optical system according to claim 2, wherein the dimension of the first unit lens in the width direction is the projection in the width direction when the reflection mirror is projected in the optical axis direction of the illumination optical system. An illumination optical system characterized by being set to 1 / n times (n is a natural number) times the dimension. 4. The illumination optical system according to claim 1, wherein at least one of the first lens portion and the second lens portion includes one plano-convex lens and the lens plate. An illumination optical system characterized by. 5. The illumination optical system according to claim 1, a light valve that forms an image by modulating light from the illumination optical system with an image signal, and the formed image on a screen. A projection type display device, comprising: a projection optical system for projecting and displaying on a screen. 6. An illumination optical system according to claim 1, a color light separating element for separating light from a light source into three color lights, and each color light being modulated by an image signal to form an image 3. A projection display comprising two light valves, a color light combining element for combining three types of images of respective color lights into one, and a projection optical system for projecting and displaying the combined image on a screen. apparatus.