JPH1114831A - Polarized light separating device, and polarized light illuminating and projection type display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the thin type polarized light separating device which separates natural light into two polarized light components having different directions and projects them in mutually different directions. SOLUTION: This polarized light separating device is constituted in a plate shape by adhering an incidence-side prism 41 having a polarized light separating film 42 vapor-deposited on its oblique surface and a projection-side prism array 43 together with a transparent adhesive 44. The projection-side prism array 43 has a lower refractive index than the incidence-side prism 41. When natural light is made incident on the incidence-side prism 41 along the optical axis, its P-polarized light component is transmitted through the polarized light separating film 42 and projected in a direction off its optical axis and the S-polarized light component, on the other hand, is reflected by the polarized light separating film 42, reflected by an adjacent polarized light separating film 42, and projected in parallel to the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization separation device for separating natural light into two linearly polarized lights having different traveling directions, a method of manufacturing the same, an illumination optical device using the polarization separation device, and a projection using the illumination optical device. The present invention relates to a type display device.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining a large screen image, a method of forming an optical image corresponding to an image signal on a light valve, irradiating the optical image with light, and enlarging and projecting the image on a screen by a projection lens has been used. Better known. Recently, a projection type display device using a liquid crystal panel as a light valve has attracted attention, for example, Japanese Patent Application Laid-Open No. 62-1334.
No. 24, which is incorporated herein by reference. The liquid crystal panel uses an active matrix type in which a twisted nematic (TN) liquid crystal is used as a liquid crystal material and a TFT is provided in each pixel as a switching element in order to obtain a high quality projected image, and is used for red, green, and blue. It is becoming mainstream to use three liquid crystal panels. Recently, the uniformity of illuminance of a projected image has been improved by using an integrator in which two lens array plates are combined.

A conventional example of the configuration of an optical system of a projection display device using a TN liquid crystal and an integrator will be described with reference to FIG. The light source 14 is composed of the lamp 11, the concave mirror 12, and the filter 13. The light emitted from the lamp 11 is converted into near parallel light by the concave mirror 12, and the filter 13 removes infrared light and ultraviolet light. Light emitted from the light source 14 is incident on the incident side lens array 15 and the exit side lens array 16.
Are incident on the integrator 17 which combines the above. The incident-side lens array 15 is a two-dimensional array of a plurality of positive lens elements 18 having the same rectangular aperture, and the emission-side lens array 16 includes a plurality of positive lens elements 19 corresponding to each positive lens element 18. They are arranged two-dimensionally. The light emitted from the integrator 17 enters a color separation optical system composed of dichroic mirrors 20 and 21 and a plane mirror 22, and is separated into light of three primary colors of red, green and blue. Each primary color light is respectively transmitted to the field lens 23, 2
4, 25, and enter the liquid crystal panels 29, 30, 31 after passing through the incident side polarizing plates 26, 27, 28. Each positive lens element 18 forms a real image corresponding to the illuminant of the lamp 11 on the corresponding positive lens element 19. Each positive lens element 19
Forms a real image corresponding to the aperture of the corresponding positive lens element 18 on each of the liquid crystal panels 26, 27, and 28, and illuminates an area slightly larger than their display area. Due to the fact that the brightness unevenness in the positive lens element 18 is smaller than the entire brightness unevenness on the incident side lens array 15 and that the output side lens array 16 forms a real image obtained by rotating the object by 180 °, the liquid crystal panels 29, Since the illuminance uniformity formed on 30 and 31 is improved, the illuminance distribution of the projected image is finally made uniform. Optical images are formed on the liquid crystal panels 29, 30, and 31 as changes in transmittance according to video signals. Outgoing lights from the liquid crystal panels 29, 30, and 31 pass through the outgoing-side polarizing plates 32, 33, and 34, respectively, and are converted into one light by a color combining optical system including dichroic mirrors 35 and 36 and a plane mirror 37. After being synthesized, the light is incident on the projection lens 38, and the three liquid crystal panels 29, 30, 3
The optical image on 1 is enlarged and projected on a screen by a projection lens 38.

[0004]

The TN liquid crystal panel used in the projection display device shown in FIG. 11 needs a polarizing plate on the incident side. The incident side polarizing plate is used to convert natural light emitted from the light source into linearly polarized light. However, since it absorbs about half of the incident light, there is a problem that the light utilization efficiency of the entire device is low.

In order to solve this problem, there has been proposed an optical system in which a polarization separation device for converting natural light into linearly polarized light and an integrator are combined. For example, JP-A-8-2
Japanese Patent No. 34205 discloses that a polarization separation film is provided between a right-angle prism and a tapered glass plate, a reflection film is provided on the opposite side of the tapered glass plate, and an incident-side lens array is arranged on the exit side of the right-angle prism. There is disclosed a polarization beam splitting device configured such that is incident on the exit lens array. However, this polarization separation device has a problem in that the right-angle prism becomes considerably large, so that the cost is high. Further, since the optical path difference between the two polarized light components differs depending on the location of the tapered glass plate, a region where the two polarized light components cannot be separated well on the exit-side lens array is generated, and the efficiency is not so high. was there.

Japanese Patent Application Laid-Open No. 8-234205 discloses a polarization separation device in which a plurality of prism elements are combined in a plate shape, and converts natural light emitted from a light source into light beams having polarization directions orthogonal to each other.
Also disclosed is a configuration in which two polarized light components are separated into two polarized light components, the two polarized light components are emitted in different directions, and the two polarized light components are transmitted through different positions of each positive lens element of the exit lens array. Have been. However, there has been a problem that the configuration of the polarization separation device is complicated and it is difficult to assemble.

Japanese Patent Application Laid-Open No. 6-202094 discloses a polarization conversion optical system combining a thin polarization separation element in which a material having refractive index anisotropy is bonded to a sawtooth prism array substrate and an integrator. Have been. Since the polarization separation element has a difference in the refractive index at the boundary surface depending on the polarization direction, the traveling direction of the outgoing light beam can be shifted between the ordinary light beam and the extraordinary light beam. However, this polarization separation element has a problem that there is no easy-to-use refractive index anisotropic material.

In addition, a polarizing beam splitter is disposed immediately after the light source to separate natural light emitted from the light source into two linearly polarized light components, one of which is a half-wave plate or a 90 ° TN
A polarization conversion optical system in which the polarization plane is rotated by 90 ° by the liquid crystal so that the traveling direction of the light beam is parallel to the traveling direction of the other light beam, and these two components are incident on the liquid crystal panel (for example, JP-A-63-271313). Gazette, JP-A-63-1686
No. 22, Japanese Patent Laid-Open No. 197913/1988 also proposes a polarization conversion optical system using two plane mirrors. However, since all the polarization separation devices have long optical path lengths, there is a problem that efficiency is not much improved when combined with an integrator, and there is a problem that the whole set becomes large.

The present invention has been made in view of the above circumstances, and has a polarization separating apparatus for separating natural light into two linearly polarized lights having different traveling directions, and a highly efficient and uniform illuminance using the polarized light separating apparatus. It is an object of the present invention to provide a polarized light illuminating device having good operability, and a projection display device which uses the polarized light illuminating device to display a projection image which is compact, bright, and has good illuminance uniformity.

[0010]

Means for Solving the Problems In order to solve the above problems, the present invention has taken the following means.

According to the first aspect of the present invention, there is provided an incidence-side prism array in which a plurality of incidence-side prisms each having a triangular cross section are formed with an incidence side surface and a sawtooth-like junction surface, and the sawtooth-like junction surface. A polarization separating film formed on each inclined surface inclined in the same direction to separate incident light into two polarized light components whose polarization directions are orthogonal to each other, a plurality of integrated prisms, and a planar emission side surface and a sawtooth shape And a light-exiting prism array joined to the light-incident-side prism array joint surface so as to form a plate-like shape as a whole.

With this configuration, natural light can be efficiently converted into linearly polarized light having the same polarization direction. In addition, the incidence-side prism array and the emission-side prism array having a saw-tooth cross-section are attached to each other, and are bonded to the joint surface. Since the polarization separation film is formed, the polarization separation device can be configured to be compact and lightweight. Also, there is no need to use a large right-angle prism, and the cost can be reduced, and the optical path difference between the two polarized light components can be greatly reduced as compared with the case where a polarization separating film is deposited on a tapered glass plate. Can be satisfactorily separated.

According to a second aspect of the present invention, in the polarization splitting device of the first aspect, the refractive index of the exit-side prism array is set lower than the refractive index of the incident-side prism.
This has an effect of separating natural light incident parallel to the optical axis into light of a polarized light component emitted parallel to the optical axis and light of a polarized light component emitted in a direction deviated from the optical axis.

According to a third aspect of the present invention, in the polarization beam splitting device according to the first or second aspect, an angle formed between the incident side surface of the incident side prism and the polarization splitting film is 45 °. According to a fourth aspect of the present invention, in the polarization beam splitting device according to any one of the first to third aspects, an angle formed between the exit side surface of the exit side prism and the polarization splitting film is set to 45 °, and natural light is enhanced. Can be efficiently separated into two polarization components,
In addition, the polarization separation device can be made compact.

According to a fifth aspect of the present invention, in the polarization beam splitting device according to any one of the first to fourth aspects, the incident side prism array is arranged continuously with one side surface of each incident side prism being aligned on the same plane. By doing so, a planar incident side surface is formed, and an effect of increasing the incident efficiency of natural light is achieved.

According to a sixth aspect of the present invention, in the polarization beam splitter according to any one of the first to fifth aspects, the exit-side prism array is made of a resin material formed by injection molding. An integrated prism array having a sawtooth cross section can be manufactured at low cost, the process of bonding the prism to the incident-side prism is facilitated, and the plate-shaped polarization separation device is easily manufactured.

According to a seventh aspect of the present invention, in the polarization beam splitting device according to any one of the first to sixth aspects, the incident side prism array and the exit side prism array are connected to each other by the incident side prism and the exit side prism array. It is bonded with a transparent adhesive having a refractive index lower than the refractive index, and has an effect of increasing the effective light use efficiency by totally reflecting natural light obliquely incident on the polarization beam splitter in the prism.

According to an eighth aspect of the present invention, there is provided a light source for emitting substantially parallel natural light, and light of two polarization components, which are emitted from the light source and whose polarization directions are orthogonal to each other, are emitted in different directions. The polarization separation device according to any one of claims 1 to 7, an incidence-side lens array having a plurality of two-dimensionally arranged incidence-side lenses, and arranged near the emission side of the polarization separation device, An emission-side lens array having a plurality of emission-side lenses that make a pair with the incidence-side lens and receiving light emitted from the incidence-side lens array, and being disposed near the incident side or the emission side of the emission-side lens array. A configuration including a polarization direction correction unit that converts light of two polarization components into light with the same polarization direction is adopted.

According to this configuration, it is possible to efficiently irradiate the area to be illuminated with light having a nearly uniform illuminance distribution and near linearly polarized light.

According to a ninth aspect of the present invention, in the polarized light illuminating apparatus according to the eighth aspect, the light axis of the light source and the optical axis of the polarized light separating means are parallel, and the two polarized light components emitted from the polarized light separating means are emitted. The normal direction of the incident side lens array and the normal direction of the exit side lens array are parallel to each other. In addition, the components from the light source to the irradiated area are arranged on one axis, and an effect of simplifying a housing for mounting the components is achieved.

According to a tenth aspect of the present invention, there is provided the polarized light illuminating apparatus according to the eighth aspect, wherein the optical axis of the light source, the optical axis of the polarization splitting means, the normal direction of the entrance lens array, and the normal direction of the exit lens array. Are parallel to each other, and the center of the aperture of each of the incident-side lenses is decentered from the optical axis, so that each of the incident-side lenses has its two polarized light components centered on the normal direction of the incident-side lens array. It has the effect of proceeding in a substantially symmetrical direction.

According to an eleventh aspect of the present invention, in the polarized light illuminating device according to the eighth aspect, the incident side of the incident side lens array is a plane, and the polarization splitting device and the incident side lens array are joined. There is no need to form an anti-reflection film on the exit side of the separation device and on the entrance side of the incident lens array, so that the effect of reducing costs can be achieved.

According to a twelfth aspect of the present invention, in the polarized light illuminating apparatus according to the eighth aspect, a positive lens is disposed near the exit side of the exit side lens array, and the real image of the aperture of each entrance side lens is located near the irradiated area. Thus, the illuminance distribution is nearly uniform in the irradiated area, and light close to linearly polarized light can be efficiently irradiated.

According to a thirteenth aspect of the present invention, there is provided a light source for emitting substantially parallel natural light, an incident-side lens array having a plurality of two-dimensionally arranged incident-side lenses and receiving light emitted from the light source, The polarization separation device according to any one of claims 1 to 7, wherein light emitted from the incident-side lens array enters and emits light of two polarization components whose polarization directions are orthogonal to each other in different directions. An emission-side lens array having a plurality of emission-side lenses that make a pair with the incidence-side lens, and receiving the light emitted from the polarization separation device, and the two light-emitting elements arranged near the incidence side or the emission side of the emission-side lens array. A configuration including a polarization direction correcting means for converting light of a polarization component into light with a uniform polarization direction is adopted.

With this configuration, since the luminance distribution in the incident side lens has a smaller change than the luminance distribution in the incident side lens array, the illuminance distribution becomes flat on the irradiated area, and the efficiency of light close to linearly polarized light is reduced. Irradiation can be performed well.

According to a fourteenth aspect of the present invention, in the polarized light illuminating apparatus according to the eighth or thirteenth aspect, the polarization direction correcting means changes one polarization direction of the two polarization components on the aperture of the exit lens. It is not changed at all or rotated by a predetermined angle α, and the other polarization direction is rotated by approximately (α + 90 °) or approximately (α-90 °), and the polarization direction is aligned with the exit-side lens array. Light that is close to linearly polarized light is incident, and has the effect of irradiating light that is close to linearly polarized light to the irradiated area.

According to a fifteenth aspect of the present invention, in the polarized light illuminating apparatus according to the thirteenth aspect, the optical axis of the light source, the normal direction of the incident side lens array, the optical axis of the polarization splitting means, and the output side lens array. The normal directions are parallel to each other, and each output-side lens moves the center of the aperture of each output-side lens so that the two polarized light components travel in parallel with the normal direction of the output-side lens array. It is decentered from the axis, and has the effect of simplifying the housing in which the components from the light source to the irradiated area are arranged on one axis and in which the components are mounted.

According to a sixteenth aspect of the present invention, in the polarized light illuminating apparatus according to the thirteenth aspect, the outgoing side of the incident side lens array is a plane, and the incident side lens array and the polarization splitting device are joined. There is no need to form an anti-reflection film on the exit side of the separation device and on the entrance side of the incident lens array, so that the effect of reducing costs can be achieved.

According to a seventeenth aspect of the present invention, in the polarized light illuminating apparatus of the thirteenth aspect, a positive lens is disposed near the exit side of the exit side lens array, and the real image of the opening of each entrance side lens is located near the irradiated area. Thus, the illuminance distribution is nearly uniform in the irradiated area, and light close to linearly polarized light can be efficiently irradiated.

The invention according to claim 18 provides the polarized light illuminating device according to any one of claims 8 to 12, which irradiates light near linearly polarized light to the irradiation area, and outputs the light emitted from the polarized light illuminating device. A light valve that forms an optical image as a change in receiving polarization state; and a projection lens that projects light emitted from the light valve and projects the optical image. A configuration is employed in which the output light from the projection lens is set to be substantially maximum when the bulb has the maximum transmittance.

According to this configuration, natural light emitted from the light source is efficiently converted to light close to linearly polarized light, and the light close to linearly polarized light efficiently passes through the incident-side polarizing plate. This has the effect of improving the efficiency and improving the uniformity of the illuminance of the projected image.

According to a nineteenth aspect of the present invention, there is provided the polarized light illuminating apparatus according to any one of the thirteenth to seventeenth aspects, wherein light near linearly polarized light is radiated to the irradiated area. A light valve that forms an optical image as a change in receiving polarization state; and a projection lens that projects light emitted from the light valve and projects the optical image. The output light from the projection lens is set to be substantially maximum when the bulb has the maximum transmittance.Since light close to linearly polarized light efficiently passes through the incident-side polarizing plate, light absorption is reduced. This has the effect of achieving high light use efficiency and good illuminance uniformity of the projected image.

[0033]

Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a configuration of a polarization beam splitting apparatus according to Embodiment 1 of the present invention. The polarization splitting device shown in the figure has an incident-side prism array 40 in which a plurality of incident-side prisms 41 are arranged so as to have a saw-tooth cross-section, and is formed on one surface of each of the incident-side prisms 41 on a saw-tooth forming surface side. And an emission-side prism array 43 in which each incidence-side prism 41 is joined to one surface having the same shape as the sawtooth-formed surface.

FIG. 2 shows a partial cross section of the polarized light separating apparatus. The incident side prism 40 has a right-angled isosceles triangle in cross section, and a polarization separation film 42 is deposited on a slope adjacent to two side surfaces (a bottom surface and a back surface) forming a right angle. The incident side prism array 40 includes each of the incident side prisms 41.
Are formed on the back surface of the light-emitting device, and a plurality of incident-side prisms 40 are arranged such that the inclined surfaces of the incident-side prism 40 on which the polarization separation films 42 are formed are parallel to each other. On the other hand, the exit-side prism array 43 has a structure in which right-angled isosceles triangular prisms having the same shape as the incident-side prism 40 are two-dimensionally arranged and integrated. The joining surface side of the emission-side prism array 43 has a sawtooth shape, and the emission side surface 48
Is a plane. The surface on which the polarization splitting film is formed and the bottom surface of the incident-side prism 41 are bonded to the sawtooth-formed surface of the emission-side prism array 43 with a transparent adhesive 44. Anti-reflection films 45 and 4 are provided on the entrance side surface 47 of the entrance side prism array 40 and the exit side surface 48 of the exit side prism array 43, respectively.
6 has been deposited.

The refractive index of the exit-side prism array 43 is lower than the refractive index of the entrance-side prism 41. The polarization separating film 42 is formed by alternately stacking low-refractive-index films and high-refractive-index films. Further, the refractive index of the transparent adhesive 44 is
It is slightly lower than the refractive index of the exit side prism array 43.

The operation of the thus-configured polarization separation device will be described with reference to FIG. Natural light 51 is optical axis 5
Incident on the incident side surface 47 of the polarization separation device along 2
The light passes through the incident-side prism 41 and enters the polarization splitting film 42 at an angle of 45 °. The polarization separation film 42 functions to transmit most of the P-polarized light component and reflect most of the S-polarized light component.

The light 53 of the P-polarized light component transmitted through the polarization separation film 42 is set so that the refractive index of the exit-side prism array 43 is lower than the refractive index of the incident-side prism 41. Out along the oblique direction 54. Further, the S-polarized light component 55 is reflected by the polarization separation film 42 of the adjacent incident side prism 41 and emitted parallel to the optical axis 52 because the polarization separation films 42 are arranged in parallel with each other.

As described above, the emission side surface 48 of the polarization separation device is used.
The light 53 of the P-polarized light component and the light 55 of the S-polarized light component are emitted with their traveling directions shifted from each other.

The polarization splitting device shown in FIG. 1 makes good use of total reflection as follows in order to increase the efficiency.

The incident side prism 4 is inclined with respect to the optical axis 52.
A part of the light that has entered the transparent adhesive 44 on the incident side prism side attempts to enter the transparent adhesive 44.
Is lower than the refractive index of the incident-side prism 41, and total reflection occurs at the boundary surface, so that the light incident on the incident-side prism 41 always enters the polarization splitting film.

Most of the P-polarized light component incident parallel to the optical axis passes through the polarization separation film 42 and travels in a direction deviated from the optical axis 51, and exits without entering the transparent adhesive 44. The light exits from the side prism array 43. A part of the P-polarized light component incident on the incident side prism 41 obliquely with respect to the optical axis 52 is totally reflected by the transparent adhesive 44 and then emitted from the emission side prism array 43. The former light is emitted in a predetermined angle range around the direction 54, and the latter light is also emitted in this angle range.

When the refractive index of the exit-side prism array 43 is higher than the refractive index of the entrance-side prism 41, a part of the light of the P-polarized component transmitted through the polarization splitting film 42 is transparent to the exit-side prism array 43. There is a disadvantage that part of the light of the P-polarized light component is emitted in an angle range different from the angle range in which the light of the P-polarized light component is totally reflected at the boundary surface with the adhesive 44 and most of the light of the P-polarized light component is emitted.

The light shown by the solid line in FIG. 2 is a part of the S-polarized light component reflected by the polarization splitting film 42.
The light enters the outgoing side surface 48 of the third light-emitting element 3, and is totally reflected therefrom before being incident on the adjacent polarization splitting film 42. Further, light indicated by a dotted line in FIG.
Is a part of the light of the S-polarized light component that travels through the exit-side prism array 43 along the axis. This light enters the transparent adhesive 44, is totally reflected there, and then exits from the exit side surface 48. At this time, since the angle formed between the polarization splitting film 42 and the optical axis 52 is 45 °, the S-polarized light 5
3 and the optical axis 52, the angle between the incident natural light 51 and the optical axis 5.
It is the same as the angle between two.

As described above, the polarization beam splitter shown in FIG. 1 can efficiently separate incident natural light into S-polarized light and P-polarized light. In order to increase the efficiency, the incident side prism 41 and the exit side prism array 4
Each of the prisms on 3 is a right-angled isosceles triangle, the refractive index of the transparent adhesive 44 is made lower than the refractive index of the exit-side prism array 43, and the entrance side surface 47 of each entrance-side prism 41.
It is preferable that both the emission side prism array 43 and the emission side surface 48 are aligned on one plane.

The refractive index of the entrance-side prism 41 is n ₁ , the refractive index of the exit-side prism array 43 is n ₂ , and the transparent adhesive 44
Is the refractive index of n _A , the critical angle of total reflection θ _{1T of the} surface where the incident side prism 41 contacts the transparent adhesive 44 and the critical angle of total reflection θ of the surface where the exit side prism array 43 contacts the transparent adhesive 44 _2T is as follows.

[0047]

(Equation 1)

[0048]

(Equation 2) By using (Equation 1) and (Equation 2), the refractive index of the transparent adhesive 44 may be made slightly lower than the refractive index of the emission-side prism array 43 so that all effective light is totally reflected. In this case, if the difference between the refractive index of the transparent adhesive 44 and the refractive index of the emission-side prism array 43 is too large, the transmittance for the P-polarized light component decreases, so that the refractive index of the transparent adhesive 44 is It may be slightly lower than the refractive index of the array 43.

Further, by increasing the number of prisms on the entrance-side prism 41 and the exit-side prism array 43, the thickness of the polarization separation device can be reduced. This is very convenient when a polarization separation device and an integrator are combined as described later.

Next, the polarization separation characteristics of the polarization separation film 42 will be described.

When the incident angle and the refraction angle are Brewster's angle at the interface between the layers of the polarization separation film 42, the transmittance of the P-polarized light component at one interface is ideally 100%,
The transmittance of the S-polarized light component is lower than 100%. Therefore, if the number of layers of the polarization separation film 42 is increased, the P-polarized light transmittance can be set to a value close to 100%, and the S-polarized light transmittance can be extremely reduced. Further, by optimizing the thickness of each layer of the polarization separation film 42, the S-polarized light reflectance can be made close to 100% by utilizing light interference.

The refractive index of the entrance-side prism 41 is n ₁ , the refractive index of the exit-side prism array 43 is n ₂ , and the reference incident angle in the entrance-side prism 41 (between the normal line of the polarization separation film 42 and the optical axis 52). Angle) is θ ₁ , the exit side prism array 43
When the reference emission angle and theta ₂ in the medium, the following relationship holds according to Snell's law.

[0053]

(Equation 3) In order for the angle of incidence and the angle of refraction to be the Brewster angle at the interface between the layers of the polarization separation film 42, the following conditions must be satisfied.

[0054]

(Equation 4)

[0055]

(Equation 5) The following equation is obtained from (Equation 3), (Equation 4), and (Equation 5).

[0056]

(Equation 6) As described above, it is desirable that the incident side brhythm 41 be a right-angled isosceles triangle, so that when an incident light beam enters the polarization separation device along the optical axis 52, the incident light beam passes through the polarization separation film 42 in the incidence side prism 41. The incident angle is θ ₁ = 45 °. Then, when θ ₁ = 45 ° is substituted into (Equation 6), the following is obtained.

[0057]

(Equation 7) To widen the wavelength band of the high reflectance band of S-polarized light, n _H /
Since the larger the value of n _L is, the more advantageous it is, the refractive index of the low refractive index film should be as low as possible, and the refractive index of the high refractive index film should be as high as possible. Magnesium fluoride (MgF ₂ : refractive index at e-line: 1.39), silicon dioxide (SiO ₂ : refractive index at e-line: 1.46) as the low refractive index film, and zirconium dioxide (ZrO ₂ : e-line refractive index 2.00), tantalum pentoxide (Ta)
₂ O _5: refractive index 2.10 at e-line), titanium dioxide _(TiO 2: refractive index 2.25 at e-line), and the like. By substituting n _L and n _H into (Equation 7), the optimum refractive index of the entrance-side prism 41 is obtained. This refractive index and (Equation 3)
Is used, the relationship between the refractive index n ₂ of the exit-side prism array 43 and the refraction angle θ ₂ in the exit-side prism array 43 is determined.

The spectral transmittance characteristics of the polarized light separating film 42 with respect to the S-polarized light include the case where the light beam enters the polarized light separating film 42 from the incident side prism 41 and the case where the light beam is transmitted from the emitting side prism array 43 to the polarized light separating film 42. And when the light is incident on This is because the incident angle when entering the polarization separation film 42 is the same, but the refractive index is different between the incident side prism 41 and the exit side prism array 43. The wavelength band of the band is shifted to a longer wavelength side than that of the former. Since the product of the former S-polarized light reflectance and the latter S-polarized light reflectance is dominant in the transmission efficiency of the S-polarized light of the polarization separation device, the wavelength band of the high reflectance band of both S-polarized light reflectance is obtained. Need to be a little wider.

A specific example of the polarization separation device shown in FIG. 1 will be described.

The external dimensions are 70 mm × 70 mm, and the number of prisms on the entrance-side prism 41 and the exit-side prism array 43 is 14 each. Each prism is arranged at intervals of 5 mm. Incident side prism 41
Is an optical glass SK5 manufactured by SCHOTT (refractive index 1.591 at e-line), and the exit side prism array 43 is an acrylic resin material (PMMA: e) processed by injection molding.
The refractive index of the polarized light is 1.498).
Are MgF ₂ as a low refractive index film and Zr as a high refractive index film.
O ₂ is used. The transparent adhesive 44 has a refractive index of 1.41.
Is used.

When a light beam is perpendicularly incident on the incident side prism 41 from the air, the incident angle on the polarization splitting film 42 in the incident side prism 41 is θ ₁ = 45 °, and the refraction angle in the exit side prism array 43 is θ ₂ = 48.7 °, and the light beam is bent by 3.7 ° before and after the polarization separation film 42. The angle of incidence on the exit side surface 48 is 3.4 ° and the angle of refraction is 5.5 °. Therefore, the S-polarized light component and the P-polarized light component are emitted in directions different by 5.5 °.

Using (Equation 1) and (Equation 2), when the refractive index of the transparent adhesive 44 is 1.41, θ _1T = 62.4.
°, θ _2T = 70.3 °, which is large enough to totally reflect light incident on the boundary surface.

Table 1 shows the structure of the polarization splitting film 42.

[0064]

[Table 1]

FIG. 4 shows the spectral transmittance characteristics of the polarization separation film 42.

In FIG. 4, the dotted line indicates that the incident angle is θ ₁ = 45.
Ｐ, the P-polarized light transmittance, the broken line is the S-polarized light reflectance when the incident angle is θ ₁ = 45 °, and the solid line is the S-polarized light reflectance when the incident angle is θ ₂ = 45 °.

FIG. 5 shows the spectral characteristics of the transmission efficiency of the polarization separation device when linearly polarized light is incident on the incident side prism 41 from the air along the optical axis 52.

In FIG. 5, the solid line represents the characteristic of S-polarized light, and the dotted line represents the characteristic of P-polarized light. As for the S-polarized light, the transmittance of each of the two antireflection films 45 and 46, the S-polarized light reflectance when the light is incident from the incident side prism 41 of the polarization separating film 42, and the light is incident from the emission side prism array 43 of the polarization separating film 42. This is the product of the S-polarized light reflectance in this case, and the P-polarized light is the product of the transmittance of the two antireflection films 45 and 46 and the P-polarized light transmittance of the polarization splitting film 42. FIG. 5 shows that the transmission efficiency of the polarization separation device is high.

As described above, the polarization beam splitting device according to the present embodiment can efficiently output the S-polarized light component and the P-polarized light component in slightly different directions when natural light enters, as can be seen from FIG. In addition, since the thickness in the optical axis direction is small, the optical path difference between the S-polarized light component and the P-polarized light component can be reduced.

In general, when the above-mentioned polarizing device is composed of only prisms that are used by polishing an optical glass material, the number of prisms is large, so that the number of polished surfaces and bonding surfaces is large and the cost is high. In addition, when the prism array is formed of an integral molded product on both the entrance side and the exit side, it becomes difficult to deposit a polarization separation film only on a required slope. Therefore, if only the exit side is made of a plastic material having a refractive index lower than that of optical glass and is formed as an integral injection-molded product, and only the entrance side is formed of a glass prism on which a polarization separation film is deposited, the bonding and deposition steps can be easily performed. Good mass productivity.

(Embodiment 2) FIG. 6 shows a configuration of a polarized light illuminating apparatus according to Embodiment 2 of the present invention.

In the figure, 61 is a light source, 62 is a polarization separation device, 63 is an incident side lens array, 64 is an outgoing side lens array, 65 is a polarization direction correction plate, 66 is a positive lens, 6
Reference numeral 7 denotes an irradiation area.

The polarized illumination device includes a light source 61, a polarized light separating device 62, an incident lens array 63, and an exit lens array 6.
4. It comprises a polarization direction correction plate 65 and a positive lens 66, and illuminates an irradiation area 67 arranged at a predetermined position. The incident side lens array 63, the exit side lens array 64, and the positive lens 66 constitute an integrator.

The light source 61 includes a lamp 68, a concave mirror 69, and a filter 70. The concave mirror 69 is a parabolic mirror, in which an optical multilayer film that reflects visible light and transmits infrared light is deposited on the inner surface of a glass substrate. Lamp 6
Numeral 8 is arranged such that the center of the illuminant is located at the focal point 72 of the concave mirror 69. The filter 70 is obtained by depositing an optical multilayer film that transmits visible light and reflects infrared light and ultraviolet light on one surface of a glass substrate, and deposits an anti-reflection film on the other surface. The natural light emitted from the lamp 68 is
The light is converted into near parallel light by the concave mirror 69,
After 0, only visible light is transmitted, and then enters the polarization separation device 62.

The polarization separation device 62 has the same configuration as the polarization separation device shown in FIG. When light close to parallel light emitted from the light source 61 is incident on the polarization separation device 62 along the optical axis 75, S-polarized light 76 is emitted along the optical axis 75, and P-polarized light 77 is emitted from the optical axis 75. Light is emitted along a direction inclined by the angle α. S-polarized light 76 and P-polarized light 7
7 are emitted in different directions while being almost parallel light, and all enter the incident side lens array 63.

The incident-side lens array 63 is formed by arranging a plurality of incident-side lenses 78 functioning as positive lenses on the incident side surface, and each lens element 78 has a shape similar to the effective area of the irradiated area 67 and all have the same shape. It has dimensions. The emission-side lens array 64 is formed by arranging a plurality of emission-side lenses 79 functioning as positive lenses on the emission side surface. The optical axes 80 of the respective incident-side lenses 78 are parallel to each other and coincide with the optical axes of the corresponding output-side lenses 79. The focal point of the entrance side lens 78 is located near the corresponding exit side lens 79. The focal length of each emission-side lens 79 is set such that the corresponding opening of the incidence-side lens 78 is formed on the irradiation area 67. The incident-side lens array 63 is arranged so that the traveling direction of the S-polarized light 76
The direction in which the traveling direction of the polarized light 77 is bisected is arranged so as to be parallel to the optical axis 80 of each incident side lens 78 of the incident side lens array 63.

Both the S-polarized light 76 and the P-polarized light 77 emitted from the polarization separation device 62
8 and forms a real image corresponding to the illuminant of the lamp 68 on the emission side lens 79. S-polarized light 76
And the P-polarized light 77 are both optical axes 8 of the incident side lens 78.
Since the light is incident obliquely with respect to 0, a real image corresponding to the illuminant of the lamp 68 is formed on the emission side lens 79 at a position away from the center in the opposite direction.

A polarization direction correction plate 65 is disposed near the exit side surface of the exit side lens array 64. The polarization direction correcting plate 65 has a half-wave plate 83 attached only to a region through which S-polarized light passes. The polarization direction of the S-polarized light emitted from each emission side lens 79 is rotated by 90 ° by the half-wave plate 83, and the P-polarized light emitted from each emission side lens 79 does not pass through the half-wave plate 83. Therefore, the light that has passed through the polarization direction correction plate 65 becomes light close to linearly polarized light having a uniform polarization direction. Each of the emission-side lenses 79 converts the enlarged real image of the aperture of the corresponding incidence-side lens 78 into an irradiation area 67.
Try to form.

A positive lens 66 is disposed near the exit surface of the exit lens array 64, and the focal length of the positive lens 66 is
The focal point is set so as to be located near the irradiated region 67. Therefore, the enlarged images of the openings of the respective incident-side lenses 78 formed by the respective exit-side lenses 79 overlap with each other on the irradiation target region 67. Since the luminance distribution in each incident-side lens 78 has a smaller change than the luminance distribution in the incident-side lens array 63, the illuminance distribution becomes flat on the irradiated area 67.

As described above, when the polarized light illuminating apparatus according to the present embodiment is used, it is possible to efficiently irradiate the area to be illuminated 67 with light having nearly uniform illuminance distribution and nearly linearly polarized light.

The half-wave plate 83 may be an optical crystal, a stretched resin film, or the like. Since an optical crystal is expensive, a stretched resin film is preferably used. Since the resin-stretched film has a low upper-limit temperature for use, if necessary, the film may be forcibly cooled by a cooling fan.

The polarization direction correcting plate 65 may have a half-wave plate attached to both the region where the S-polarized light passes and the region where the P-polarized light passes. In this case, the former half-wave plate rotates the polarization direction by an angle α, and the latter half-wave plate rotates the polarization direction by (α + 90 °) or (α−90 °). It is necessary to set the direction of the slow axis of the two-wave plate to a predetermined direction.

Instead of using the polarization direction correction plate 65, a half-wave plate may be attached to the plane on the entrance side or the exit side of each exit side lens 79 of the exit side lens array 64.

The transparent adhesive used for the polarization separation device 62 is
If the temperature exceeds the upper limit of the use temperature, the transmittance is lowered or peeling is caused. Therefore, it is necessary that the temperature does not exceed the upper limit of the use temperature. When the light output of the light source is large, the polarization separation device may be forcibly cooled by a cooling fan.

(Embodiment 3) FIG. 7 shows a configuration of a polarized light illuminating apparatus according to Embodiment 3 of the present invention. In FIG. 7, reference numeral 61 denotes a light source, 62 denotes a polarization separation device, and 85 denotes an incident light. Side lens array, 64 is an emission side lens array, 65
Denotes a polarization direction correction plate, 66 denotes a positive lens, and 67 denotes an irradiation area.

In the polarized light illuminating device shown in FIG. 7, the configuration of the incident side lens array 85 and the optical axis 75 of the light source 61 and the optical axis 87 of each incident side lens 86 of the incident side lens array 85 are parallel. Is different from the polarized light illumination device shown in FIG. The components other than the incident side lens array 85 are all the same as the components shown in FIG.

Each incident-side lens 86 of the incident-side lens array 85 has a light direction in which the traveling direction of the S-polarized light 88 and the traveling direction of the P-polarized light 89 emitted from the incident-side lens array 85 are equally divided into two. Each optical axis 87 is eccentric with respect to the center of each aperture so as to be parallel to the axis 75.

In the configuration shown in FIG. 7, the same operation and effect as those of the polarized light illuminating apparatus according to the third embodiment can be obtained, and all the components from light source 61 to irradiated area 67 are arranged on one axis. There is an advantage that the housing for mounting the components is simpler than the configuration shown in FIG.

In the configuration shown in FIG. 7, even if the incident side lens array 85 is configured such that the incident side is a plane and the exit side is a lens surface, the polarization separation device 62 and the incident side lens array 85 are joined with a transparent adhesive. Good. This eliminates the need to form an anti-reflection film on the emission side of the polarization separation device 62 and the incidence side of the incidence-side lens array 85, and can reduce the cost.

(Embodiment 4) FIG. 8 shows a configuration of a polarized light illuminating apparatus according to Embodiment 4 of the present invention. In FIG. 8, reference numeral 91 denotes a light source, 92 denotes an incident side lens array,
93 is a polarization beam splitter, 94 is an exit lens array, 95
Denotes a polarization direction correction plate, 96 denotes a positive lens, and 97 denotes an irradiation area.

The polarized light illuminating device shown in FIG. 8 is basically different from the polarized light illuminating device shown in FIG. 6 in that a polarized light separating device 93 is arranged on the exit side of the entrance lens array 92.

The configuration of the light source 91 is the same as the configuration of the light source 61 shown in FIG. 6. Natural light emitted from the light source 91 is incident on the incident side lens array 92, the polarization separation device 93, the exit side lens array 94, the polarization direction correction. The light passes through the plate 95 and the positive lens 96 in this order, and reaches the irradiation area 97.

The incident-side lens array 92 has a plurality of incident-side lenses 98 functioning as positive lenses arranged on the incident side surface, similarly to the incident-side lens array 63 shown in FIG. The effective area of the illuminated area 97 has a shape similar to that of the effective area and all have the same dimensions. The polarization beam splitter 93 is the same as the polarization beam splitter shown in FIG. 1. When natural light emitted from the incident side lens array 92 enters, the S-polarized light 99 and the P-polarized light 100 are emitted in different directions. The emission-side lens array 94 includes a plurality of emission-side lenses 101 functioning as positive lenses on the emission side surface, similarly to the emission-side lens array 64 shown in FIG. The horizontal pitch of the entrance-side lens array 92 and the horizontal pitch of the exit-side lens array 94 are equal to each other, and the optical axes of the entrance-side lenses 98 are parallel to each other and coincide with the optical axes of the corresponding exit-side lenses 101. ing. The optical axis of each emission side lens 101 is eccentric with respect to the center of the opening by ／ of the horizontal pitch of the emission side lens array 94. The focal point of the entrance-side lens 98 is located near the corresponding exit-side lens 101, the focal point of each exit-side lens 101 is located near the corresponding entrance-side lens 98, and the focal point of the positive lens 96 is located near the irradiation area 97. Located nearby. A half-wave plate 104 is attached only to a region through which the S-polarized light passes on the incident side of the emission-side lens array 94, and the polarization direction of the S-polarized light 99 is 90 ° by the half-wave plate 104. Rotated.

When natural light emitted from the light source 91 is incident on the incident side lens array 92, each incident side lens 98 attempts to form a real image of the light emitter of the lamp 68 constituting the light source 91 on the corresponding exit side lens 101. . When natural light emitted from the incidence-side lens array 92 enters the polarization separation device 93, the S-polarized light 99 travels along the optical axis 75, and
The polarized light 100 travels in a direction deviated from the optical axis 75, and a real image corresponding to the light emitter of the lamp 68 is formed on each of the emission-side lenses 101. Since the polarization direction of the S-polarized light 99 is rotated by 90 ° by the half-wave plate 104 and the P-polarized light 100 does not pass through the half-wave plate 104, the polarization direction is aligned with the exit-side lens array 94. Light close to linearly polarized light is incident. The two polarized light components are emitted by the respective exit-side lenses 101 in parallel with the optical axis 75 and enter the positive lens 96. Each emission-side lens 101 forms an enlarged real image of the aperture of the corresponding entrance-side lens 98 so as to overlap each other at infinity, and the positive lens 96 sets a real image at infinity as an object and outputs a corresponding image to the irradiation area 97.
Form on top. Therefore, the enlarged images of the apertures of the respective incident-side lenses 98 formed by the respective exit-side lenses 101 overlap with each other on the irradiation area 97. Since the luminance distribution in each of the incident side lenses 98 has a smaller change than the luminance distribution in the incident side lens array 92, the illuminance distribution becomes flat on the irradiated area 97.

According to the polarized light illuminating apparatus of the present embodiment, the illuminance distribution in the irradiated area 97 is almost uniform,
Light close to linearly polarized light can be efficiently emitted.

In the configuration shown in FIG. 8, the incident side lens array 92 and the polarization beam splitter 93 may be joined by a transparent adhesive. This eliminates the need to form an anti-reflection film on the exit side of the entrance-side lens array 92 and the incidence side of the polarization beam splitter 93, and can reduce the cost.

(Embodiment 5) FIG. 9 shows a configuration of a projection display apparatus according to Embodiment 5 of the present invention.
In the drawing, reference numeral 121 denotes a polarized light illuminator, 122 and 123 denote dichroic mirrors, 124 denotes a plane mirror, and 126 and
127, 128 are field lenses, 132, 133,
134 is a liquid crystal panel, 138 and 139 are dichroic mirrors, 140 is a plane mirror, and 142 is a projection lens.

The polarized light illuminating device 121 is the same as that shown in FIG. 7, and includes a light source 61, a polarized light separating device 62, an incident side lens array 63, an outgoing side lens array 64, a polarization direction correcting plate 65, and a positive lens 66. It is configured.

The light emitted from the polarization illuminator 121 enters a color separation optical system composed of a blue reflection dichroic mirror 122, a red reflection dichroic mirror 123, and a plane mirror 124, and is decomposed into red, green, and blue primary color lights. Is done.

Each primary color light emitted from the color separation optical system passes through field lenses 126, 127, 128 and incident side polarizing plates 129, 130, 131, and then enters liquid crystal panels 132, 133, 134. Each of the three liquid crystal panels 132, 133, and 134 is a TN liquid crystal panel, and forms an optical image as a change in polarization state. Each of the liquid crystal panels 132, 133, 1
The optical path length up to 34 is the same in each of the red, green, and blue optical paths, and the respective polarization axes of the incident-side polarizing plates 129, 130, and 131 match the central polarization direction of the linearly polarized light emitted from the polarization illuminating device 121. ing. Each liquid crystal panel 132, 133, 134
Outgoing light from the output side polarizing plates 135, 13 respectively.
6,137 and the blue reflecting dichroic mirror 13
8. Red reflective dichroic mirror 139, flat mirror 1
The light enters the color combining optical system constituted by 40 and is combined into one light, and then enters the projection lens 142.

Thus, the liquid crystal panels 132, 133, 1
The optical image formed at 34 is enlarged and projected on the screen.

According to such a projection type display device according to the present embodiment, the polarization separation device 62, the incident side lens array 63, the exit side lens array 64, the polarization direction correction plate 65,
By the combination of the positive lens 66, natural light emitted from the light source 61 can be efficiently converted into light close to linearly polarized light, and the light close to linearly polarized light is converted to the incident-side polarizing plates 129, 130, and 13.
Since 1 is transmitted with a high transmittance, a very high light use efficiency can be realized.

Also, the incident side polarizing plates 129, 130, 13
Since light close to linearly polarized light is incident on the light-receiving element 1, there is an advantage that light absorption by the incident-side polarizing plate is small, and the reliability is increased accordingly. Further, with the incident side lens array 63 and the exit side lens array 64, the illuminance uniformity of the projected image can be improved.

(Embodiment 6) FIG. 10 shows the configuration of a projection type display apparatus according to Embodiment 6 of the present invention. In FIG. 10, 151 is a polarized light illuminating device, 152 is a plane mirror, 153 154 is a dichroic mirror, 15
5 is a plane mirror, 156 and 157 are relay lenses, 15
8, 159 are plane mirrors, 160, 161, 162 are field lenses, 166, 167, 168 are liquid crystal panels, 172 is a color combining prism, and 173 is a projection lens.

The polarization illuminator 151 is the same as that shown in FIG. 7, and comprises a light source 61, a polarization separator 62, an incident-side lens array 63, an exit-side lens array 64, a polarization direction correction plate 65, and a positive lens 66. Have been.

The light emitted from the polarization illuminator 151 is reflected by a plane mirror 152, and then enters a color separation optical system composed of a blue transmission dichroic mirror 153, a green reflection dichroic mirror 154, and a plane mirror 155, and receives a red light. ,
Decomposed into green and blue primary light. The red primary color light enters a relay optical system including a first relay lens 156, a second relay lens 157, and two plane mirrors 158 and 159.

The blue and green primary color lights emitted from the color separation optical system and the red primary color light emitted from the relay optical system pass through the field lenses 160, 161, 162 and the incident side polarizing plates 163, 164, 165, respectively. After that, the LCD panel 1
66, 167 and 168.

The three liquid crystal panels 166, 167, 168
Are TN liquid crystal panels, each of which forms an optical image as a change in polarization state. Incident side polarizing plates 163, 164,
Each polarization axis of 165 coincides with the central polarization direction of light near linearly polarized light emitted from the polarized light illumination device 151.

Light emitted from each of the liquid crystal panels 166, 167, and 168 is output from the output-side polarizing plates 169, 170, and 1, respectively.
The light passes through 71 and enters the color combining prism 172. The color synthesizing prism 172 is formed by joining four triangular prisms such that a red reflection dichroic multilayer film and a blue reflection dichroic multilayer film are arranged in an X-shape on a slope. Each primary color light that has entered the color combining prism 172 is combined into one light by the color combining prism 171, and then enters the projection lens 173. LCD panels 166, 167,
The optical image formed at 168 is enlarged and projected on a screen by a projection lens 173.

In the configuration shown in FIG.
Since the optical path length from 51 to each of the liquid crystal panels 166, 167, and 168 is longer than the other optical paths only in the red optical path, care must be taken to effectively obtain the operation of the polarized light illuminating device. Therefore,
The equivalent optical path length of red is made equal to the optical path lengths of green and blue by the relay optical system. This point will be explained a little more.

When the near-parallel light is emitted from the polarized light illuminator 151 and the projection lens 173 is telecentric, the focal point of the first relay lens 156 is located near the second relay lens 157, 2 relay lenses 1
The focal length of the optical path 57 is substantially equal to the optical path length from the first relay lens 156 to the second relay lens 157, and the optical path length from the second relay lens 157 to the field lens 162 is the second optical path length from the first relay lens 156 to the second optical path. It is preferable that the focal length of the field lens 162 is substantially equal to the optical path length up to the second relay lens 157.

By doing so, the first relay lens 1
An image of the illuminant of the lamp 68 constituting the light source 61 is formed by the 56 near the second relay lens 157, and an object near the first relay lens 156 is moved by the second relay lens 157 near the field lens 162. Therefore, the average illuminance and the illuminance distribution near the exit side of the field lens 162 are close to the average illuminance and the illuminance distribution near the entrance side of the first relay lens 156. Thus, the optical path lengths from the polarization illuminating device 151 to the red, green, and blue liquid crystal panels 166, 167, and 168 are equivalently equalized by the relay optical system, and the operation of the polarization illuminating device of the present invention can be effectively obtained. Can be.

The projection type display device shown in FIG. 10 has the same effects as those of the projection type display device shown in FIG.

[0114]

As described above, according to the present invention, inexpensive,
A polarization illuminating device that has high mass productivity, can provide a thin polarization separation device with a small optical path difference between the S-polarized light component and the P-polarized light component, and has high efficiency and good illuminance uniformity in the irradiated area.
Further, it is possible to provide a projection type display device which has high efficiency and good illuminance uniformity of a projected image.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a polarization beam splitter according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part showing a configuration of the polarization beam splitting device according to the first embodiment.

FIG. 3 is an explanatory diagram for explaining an operation of the polarization beam splitter in the first embodiment.

FIG. 4 is a characteristic diagram showing a spectral transmittance characteristic of a polarization separation film of the polarization separation device according to the first embodiment.

FIG. 5 is a characteristic diagram showing total spectral transmittance characteristics of the polarization beam splitter according to the first embodiment.

FIG. 6 is a schematic configuration diagram showing a configuration of a polarized light illumination device according to a second embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a configuration of a polarized light illumination device according to a third embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a configuration of a polarized light illumination device according to a fourth embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a configuration of a projection display apparatus according to Embodiment 5 of the present invention.

FIG. 10 is a schematic configuration diagram showing a configuration of a projection display apparatus according to Embodiment 6 of the present invention.

FIG. 11 is a schematic configuration diagram showing an example of a conventional projection display device.

[Explanation of symbols]

41 Incident side prism 42 Polarized light separating film 43 Outgoing side prism array 44 Transparent adhesive 45, 46 Antireflection film element 61, 91 Light source 62, 93 Polarized light separating device 63, 85, 92 Incident side lens array 64, 94 Outgoing side lens array 65,95 Polarization direction correction plate 66,96 Positive lens 67,97 Irradiated area 68 Lamp 69 Concave mirror 70 Filter 121,151 Polarized illumination device 132,133,134,166,167,168 Liquid crystal panel 126,127,128,160 , 161, 162 Field lens 129, 130, 131, 163, 164, 165 Input-side polarizing plate 135, 136, 137, 169, 170, 171 Output-side polarizing plate 142, 173 Projection lens 122, 123, 138, 139, 153 , 154 dichroic mirror 1 4,140,155,158,159 plane mirror 155, 156 relay lens 172 color combining prism

Claims (19)

[Claims] 1. An incidence-side prism array in which a plurality of incidence-side prisms each having a triangular cross section are formed with an incidence side surface and a sawtooth-like junction surface, and the sawtooth-like junction surface is inclined in the same direction. A polarized light separating film formed on each inclined surface to separate incident light into two polarized light components whose polarization directions are orthogonal to each other, and a planar emitting side surface composed of a plurality of integrated prisms and a sawtooth-shaped joint surface are formed. And a light exiting prism array joined to the joining surface of the incident side prism array so as to form a plate as a whole. 2. The polarization splitting device according to claim 1, wherein the refractive index of the output side prism array is lower than the refractive index of the incident side prism. 3. The polarization beam splitting device according to claim 1, wherein an angle between the incident side surface of the incident side prism and the polarization beam splitting film is 45 °. 4. An apparatus according to claim 1, wherein an angle formed between the exit side surface of the exit side prism and the polarization separation film is 45 °.
The polarization separation device according to any one of the above. 5. The incident-side prism array according to claim 1, wherein one side surface of each of the incident-side prisms is arranged on the same plane and arranged continuously to form a planar incident side surface. The polarization separation device according to any one of the above. 6. The polarization separation device according to claim 1, wherein the emission side prism array is a resin material formed by injection molding. 7. The incident side prism array and the exit side prism array are joined with a transparent adhesive having a refractive index lower than that of the incident side prism and the exit side prism array. Item 7. The polarized light separation device according to any one of Items 6. 8. A light source that emits substantially parallel natural light, and a light source that emits light from the light source and whose polarization directions are orthogonal to each other.
The polarization splitting device according to any one of claims 1 to 7, which emits light of two polarization components in different directions, and an emission side of the polarization splitting device, comprising: a plurality of two-dimensionally arranged incident-side lenses. An incident-side lens array disposed in the vicinity, an exit-side lens array having a plurality of exit-side lenses paired with the respective incident-side lenses, and receiving light emitted from the incident-side lens array; and the exit-side lens A polarized light illuminating device comprising: a polarization direction corrector disposed near an incident side or an output side of an array and configured to convert the two polarized light components into light having the same polarization direction. 9. The optical axis of the light source and the optical axis of the polarization separation means are parallel to each other, and the direction in which the traveling direction of the light of the two polarization components emitted from the polarization separation means is divided into two equal parts and the direction of the incident side lens array. 9. The polarization illuminating device according to claim 8, wherein a normal direction is parallel to the normal direction of the incident side lens array, and a normal direction of the output side lens array is parallel to the normal direction. 10. The optical axis of the light source, the optical axis of the polarization splitting means, the normal direction of the entrance lens array, and the normal direction of the exit lens array are parallel to each other.
The center of the aperture of each of the incident-side lenses is decentered from the optical axis such that the light of the two polarization components travels in a direction substantially symmetric about the normal direction of the incident-side lens array. 9. The polarized light illumination device according to 8. 11. The polarized light illuminating device according to claim 8, wherein the incident side of the incident side lens array is a flat surface, and the polarization splitting device and the incident side lens array are joined. 12. The lens system according to claim 8, wherein a positive lens is arranged near the emission side of the emission side lens array, and the real images of the apertures of the respective incidence side lenses substantially overlap each other in the vicinity of the irradiated area. Polarized lighting equipment. 13. A light source for emitting substantially parallel natural light, an incident-side lens array having a plurality of two-dimensionally arranged incident-side lenses, and receiving light emitted from the light source, and The polarization splitting device according to any one of claims 1 to 7, wherein each of the incident-side lenses is paired with a corresponding one of the polarization-separating devices. An output-side lens array having a plurality of output-side lenses to be formed, on which the output light of the polarization splitting device is incident; A polarized light illuminating device comprising: a polarized light direction correcting unit that converts light into a light having a uniform direction. 14. The polarization direction correcting means does not change the polarization direction of one of the two polarization components on the aperture of the emission-side lens at all, or rotates the polarization direction by a predetermined angle α, and substantially changes the polarization direction of the other. 14. The polarized light illuminating device according to claim 8, wherein the light is rotated by approximately (α + 90 °) or substantially (α−90 °) to irradiate the irradiated region with light close to linearly polarized light. 15. The optical axis of the light source, the normal direction of the incident-side lens array, the optical axis of the polarization splitting means, and the normal direction of the output-side lens array are parallel to each other. 2. The center of the aperture of each of the emission-side lenses is decentered from the optical axis such that the light of the two polarization components travels in parallel with the normal direction of the emission-side lens array.
4. The polarized light illumination device according to 3. 16. The polarized light illuminating device according to claim 13, wherein the exit side of the incident side lens array is a flat surface, and the incident side lens array and the polarization separation device are joined. 17. The apparatus according to claim 13, wherein a positive lens is disposed near the light exit side of the light exit side lens array, and the real images of the apertures of the light entrance side lenses substantially overlap each other near the irradiated area. Polarized lighting equipment. 18. The polarized light illuminating device according to claim 8, wherein light near linearly polarized light is radiated to the irradiation area, and the light emitted from the polarized light illuminating device is changed in polarization state. A light valve for forming an optical image, and a projection lens for projecting the optical image with light emitted from the light valve incident thereon, and the polarization direction of the light emitted from the polarized light illumination device is such that the light valve has a maximum transmittance. Wherein the output light from the projection lens is set so as to be substantially maximum when the projection display device is turned on. 19. The polarized light illuminating device according to claim 13, which irradiates light near linearly polarized light to the irradiated area, and receiving the light emitted from the polarized light illuminating device as a change in polarization state. A light valve for forming an optical image, and a projection lens for projecting the optical image with light emitted from the light valve incident thereon, and the polarization direction of the light emitted from the polarized light illumination device is such that the light valve has a maximum transmittance. Wherein the output light from the projection lens is set so as to be substantially maximum.