JP2000298212A - Optical device, production thereof and projection-type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent loss of light in a polarization converting device. SOLUTION: A first light-transmitting member 321 and a second light- transmitting member 322 each in a planer form are prepared. The first light- transmitting member 321 has first and second surfaces (film-forming surfaces) almost parallel to each other. A polarization separating film 331 is formed on the first filmforming surface. A reflecting film 332 is formed on the second film-forming surface. These films are not formed on the surfaces of the second light-transmitting member 322. Then a plurality of the first light-transmitting members 321 and a plurality of the second light-transmitting members 322 are laminated alternately. The laminated light-transmitting members are cut at a prescribed angle from the surface, and the cut face is polished to form a polarization beam splitter array 320.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element, a manufacturing method therefor, and a projection display device having the optical element.

[0002]

2. Description of the Related Art As an optical element (polarization conversion element) for converting light having a random polarization direction into light having a single polarization direction, one described in JP-A-7-294906 is known. ing. FIG. 1A is a plan view of such an optical element, and FIG. 1B is a perspective view thereof. This optical element includes a polarization beam splitter array 22 in which linear polarization beam splitters 30 having a polarization separation film 36 and linear prisms 40 having a reflection film 46 are alternately bonded. A part of the exit surface of the polarizing beam splitter array 22 has a λ / 2 retardation plate 2.
4 are selectively provided.

A linear polarizing beam splitter 30 has two right-angle prisms 32 and 34 and these right-angle prisms 3 and 34.
Polarization separation film 3 formed on the boundary surface that is the slope of 2, 34
6. When manufacturing the polarization beam splitter 30, after forming the polarization separation film 36 on the slope of one of the right-angle prisms, the two right-angle prisms 32 and 34 are formed.
Is bonded with an optical adhesive.

[0004] The linear prism 40 has two right-angle prisms 42 and 44 and a reflection film 46 formed on a boundary surface that is a slope of the right-angle prisms 42 and 44. When manufacturing this prism 40, after forming a reflective film 46 on the slope of one of the right-angle prisms, the two right-angle prisms 42 and 44 are bonded with an optical adhesive. The reflection film 46 is formed of a metal film such as an aluminum film.

The plurality of linear polarization beam splitters 30 thus prepared and the plurality of linear prisms 40 are alternately bonded with an optical adhesive to form a polarization beam splitter array 22. Then, the λ / 2 phase difference plate 24 is selectively attached to the exit surface of the polarization beam splitter 30.

[0006] From the light incident surface, incident light including an s-polarized component and a p-polarized component is incident. This incident light is first separated by the polarization separation film 36 into s-polarized light and p-polarized light.
The s-polarized light is substantially vertically reflected by the polarization splitting film 36, further vertically reflected by the reflection film 46, and emitted from the prism 40. On the other hand, the p-polarized light passes through the polarization separation film 36 as it is, and is
The light is converted into polarized light and emitted. Therefore, the light beams having random polarization directions incident on this optical element are all s
The light is emitted as a polarized light beam.

[0007]

In the conventional optical element shown in FIG. 1, four right-angle prisms 32, 34, 42, 44 are provided.
Are bonded with an optical adhesive. Therefore,
The s-polarized light and p-polarized light must pass through the optical adhesive layer formed at the boundary of the prism many times between the time when the light enters the optical element and the time when the light exits. Since the optical adhesive layer absorbs light to some extent, the intensity of light decreases each time the light passes through the optical adhesive layer. As a result, there is a problem that the light use efficiency is considerably reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to provide a technique capable of increasing the efficiency of light utilization in an optical element.

[0009]

In order to solve at least a part of the above-mentioned problems, a first aspect of the present invention is an optical element, comprising: a light incident surface; and a light incident surface substantially parallel to the light incident surface. A substantially parallel first light emitting surface having a predetermined angle with the light incident surface and the light emitting surface.
And a first film forming surface, a polarization separating film formed on the first film forming surface, and a reflective film formed on the second film forming surface. A light-transmitting member and light that are alternately bonded to the plurality of first light-transmitting members and are formed on the same plane as the light-incident surface and the light-emitting surface of the plurality of first light-transmitting members. And a plurality of second translucent members each having an incident surface and a light exit surface.

According to the first aspect, of the light incident from the light incident surface of the first translucent member, the polarized light component reflected by the polarization separation film does not pass through the optical adhesive layer. The light is reflected by the reflection film, and then emitted from the polarizing beam splitter. Accordingly, the number of times that the polarized light component passes through the optical adhesive layer can be reduced, so that the light use efficiency can be increased.

In the first aspect, it is preferable that the reflection film is formed of a dielectric multilayer film.

In a reflection film formed of a dielectric multilayer film, the reflectance of a specific linearly polarized light component can be increased as compared with a metal reflection film such as an aluminum film. Therefore, it is possible to further enhance the light use efficiency.

[0013] In the first aspect, further, a polarization direction changing means provided corresponding to the light emitting surface of the first light transmitting member or the light emitting surface of the second light transmitting member. It is preferable to provide

The linearly polarized light components having different polarization directions are emitted from the light emitting surface of the first light transmitting member and the light emitting surface of the second light transmitting member. Therefore, by providing the polarization direction converting means in any one of them, it is possible to convert all the light beams emitted from the optical element into one linearly polarized light component.

[0015] In the first invention, it is preferable that a light-shielding means is further provided corresponding to the light incident surface of the second translucent member.

If light enters from the light incident surface of the second translucent member, this light is reflected by the reflection film,
The light passes through the optical adhesive layer many times while being separated into s-polarized light and p-polarized light by the polarization separation film. Therefore, if such light is shielded by providing a light shielding means corresponding to the light incident surface of the second translucent member, the light incident on the optical element can pass through the optical adhesive layer many times. Can be prevented.

[0017] In the first aspect of the present invention, the first aspect is provided.
And an adhesive layer at a boundary surface between the first and second light-transmitting members, and the first and second light-transmitting members are arranged such that a distance between the polarization separation film and the reflection film becomes substantially equal through the optical element. It is preferable that at least a part of the thickness of the light transmitting member and the thickness of the adhesive layer is set.

In this case, since the distance between the polarization splitting film and the reflection film becomes equal, the positional accuracy of the film in the optical element is improved, and the light use efficiency is improved.

[0019] In the first aspect of the present invention, the second aspect
It is preferable that the thickness of the light transmitting member is set smaller than the thickness of the first light transmitting member. In this case, the distance between the polarization separation film and the reflection film can be made equal to improve the light use efficiency of the optical element.

The thickness of the second light-transmitting member is the same as that of the first light-transmitting member.
Preferably, the thickness is in the range of about 80% to about 90% of the thickness of the light transmitting member.

The thickness of the first light-transmitting member may be made substantially equal to a value obtained by adding twice the thickness of the adhesive layer to the thickness of the second light-transmitting member. preferable.

Further, the optical element is an optical element used together with a plurality of small lenses arranged on the light incident surface side of the optical element, and a distance between the plurality of polarization separation films in the optical element. Is preferably set so as to substantially correspond to the pitch of the plurality of small lenses.

With this configuration, the plurality of light beams emitted from the plurality of small lenses can be configured to be incident on the corresponding polarization separation films, so that the light use efficiency is improved.

As an example, an adhesive layer is provided at a boundary between the first and second translucent members, and a distance between the plurality of polarization separation films is smaller than that of the plurality of small lenses. At least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is set to substantially correspond to the pitch of the lens optical axis.

Alternatively, the plurality of small lenses have a plurality of different lens optical axis pitches, and an interval between the plurality of polarization separation films substantially corresponds to the plurality of different lens optical axis pitches. Preferably, at least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is set.

In this way, even when the pitch of the lens optical axis is different, the light flux emitted from each small lens can be configured to be incident on the corresponding polarization separation film. Is improved.

In the first invention, the optical element is an optical element used together with a plurality of small lenses arranged on the light incident surface side of the optical element, and the plurality of optical elements in the optical element are provided. It is preferable that an interval between the polarization splitting films is set to substantially correspond to a pitch of a plurality of light beams emitted from the plurality of small lenses.

The pitch of the light beam emitted from the small lens is
It does not always coincide with the pitch of the lens optical axis.
Even in such a case, the light beams emitted from the respective small lenses can be configured to be incident on the corresponding polarization separation films, so that the light use efficiency is improved.

As an example, an adhesive layer is provided at a boundary between the first and second light-transmissive members, and a distance between the plurality of polarization separation films is larger than that of the plurality of small lenses. To correspond approximately to the pitch of the plurality of emitted light beams,
At least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is set.

According to a second aspect of the present invention, there is provided a method of manufacturing an optical element, comprising: (a) polarization separation on the first surface of a first light-transmitting plate having substantially parallel first and second surfaces; Forming a film, (b) forming a reflective film on the second surface of the first light-transmissive plate, and (c) forming a plurality of polarized light separating films and a plurality of reflective films formed thereon. (D) alternately bonding the first light-transmissive plate material and a plurality of second light-transmissive plate materials each having two substantially parallel surfaces;
A step of cutting the translucent plate members alternately bonded at a predetermined angle with respect to the first and second surfaces to generate an optical element block having a light entrance surface and a light exit surface that are substantially parallel to each other. And the following.

According to the second aspect, the optical element according to the first aspect can be easily formed. Therefore, an optical element with high light use efficiency can be manufactured.

In the second invention, (e)
Preferably, a step of polishing the light incident surface and the light exit surface of the optical element block is provided.

In this case, since the light incident surface and the light exit surface of the optical element block serving as the optical element can be easily polished, the optical element can be easily manufactured.

In the second aspect, the step (c)
Preferably, the method preferably includes a step of alternately laminating a plurality of the first translucent plate members and a plurality of the second translucent plate members via a photocurable adhesive layer and bonding them by light irradiation. .

In this case, since the optical adhesive can be cured by irradiating the bonded plate material with light, the manufacture of the optical element is easy.

Alternatively, in the step (c), (1) a photo-curable adhesive layer is interposed between one sheet of the first light-transmitting member and one sheet of the second light-transmitting member. (2) irradiating the laminate with light to cure the photocurable adhesive layer, and (3) applying the photocurable material to the laminate. The first light-transmissive member and the second light-transmissive member are alternately overlapped with each other via an adhesive layer. In this case, light is applied to the laminate every time one member is overlapped. Curing the photo-curable adhesive layer.

With this configuration, the adhesive is cured each time one translucent member is stacked, so that the positional relationship between the translucent members can be set with high accuracy.

Alternatively, in the step (c), (1) a photocurable adhesive layer is interposed between one sheet of the first light transmitting member and one sheet of the second light transmitting member. (2) irradiating the laminated body with light to cure the photocurable adhesive layer, and (3) performing the steps (1) and (2). ), The plurality of laminates are alternately stacked via the photocurable adhesive layer. At this time, the light-curable adhesive layer is irradiated by irradiating light each time one laminate is stacked. And a step of curing.

According to this method as well, the adhesive is cured each time one laminate is stacked, so that the positional relationship between adjacent light-transmitting members can be accurately set.

The light irradiation is preferably performed from a direction that is not parallel to the surface of the light transmitting member.

In this case, since the adhesive is efficiently irradiated with light, the curing time of the adhesive can be shortened, and the throughput of manufacturing the optical element can be improved.

A third invention is a projection display device,
Any one of the above optical elements, a polarization conversion unit that converts light emitted from the optical element into one type of polarized light, and modulates the light emitted from the polarization conversion unit based on a given image signal. A modulation unit; and a projection optical system that projects the light beam modulated by the modulation unit.

According to the third aspect, since the optical element having high light use efficiency is used, the image projected on the projection surface can be brightened.

[0044]

DETAILED DESCRIPTION OF THE INVENTION First Embodiment: Next, an embodiment of the present invention will be described based on an embodiment. 2 and 3
FIG. 4 is a process cross-sectional view showing main processes for manufacturing the polarizing beam splitter array according to the first embodiment of the present invention.

In the step of FIG. 2A, a plurality of plate-shaped first light-transmitting members 321 and a plurality of second light-transmitting members 322 are prepared. A polarization splitting film 331 is formed on one of two substantially parallel surfaces (film forming surfaces) of the first light transmitting member 321. On the other surface, a reflection film 332 is formed. None of these films is formed on the surface of the second light transmitting member 322.

As the first and second translucent members 321 and 322, sheet glass is used. However, it is also possible to use a translucent plate material other than glass. Further, one of the first and second translucent members may be made of a material having a color different from that of the other. In this case, there is an advantage that the two members can be easily distinguished after the completion as a polarizing beam splitter array.
For example, one member is formed of a colorless and transparent plate glass,
The other may be formed of a transparent blue plate glass. In addition, as a sheet glass, a polished sheet glass and a float glass are preferable, and especially a polished sheet glass is preferable.

The polarized light separating film 331 is a film having a property of selectively transmitting one of s-polarized light and p-polarized light and selectively reflecting the other. Normally, the polarization separation film 3 is formed by laminating a dielectric multilayer film having such properties.
31 are formed.

The reflection film 332 is formed by laminating a dielectric multilayer film. Of course, the dielectric multilayer film forming the reflection film 332 has a different composition and configuration from those forming the polarization separation film 331. Reflective film 33
2 is a dielectric multilayer film that selectively reflects only the linearly polarized light component (s-polarized light or p-polarized light) reflected by the polarization separation film 331 and does not reflect other linearly polarized light components. preferable.

The reflection film 332 may be formed by evaporating aluminum. When the reflection film 332 is formed of a dielectric multilayer film, a specific linearly polarized light component (for example, s-polarized light) can be reflected at a reflectance of about 98%. On the other hand, the reflectance of an aluminum film is at most about 92%. Therefore, if the reflective film 332 is formed of a dielectric multilayer film, the amount of light emitted from the polarizing beam splitter array can be increased. Further, since the dielectric multilayer film absorbs less light than the aluminum film, there is also an advantage that heat generation is small. In order to improve the reflectance of a specific linearly polarized light component, the reflection film 3
It is sufficient to optimize the thickness of each film constituting the dielectric multi-layer film constituting the 32 (usually a structure in which two kinds of films are alternately laminated) or the material of the film.

In the step shown in FIG. 2B, the first and second translucent members 321 and 322 are alternately bonded with an optical adhesive. As a result, the optical adhesive layer 325 is formed between the polarization separation film 331 and the second light transmitting member 322, and
It is formed between the reflection film 332 and the second translucent member 322, respectively. 2 and 3, the thickness of each layer 331, 332, 325 is exaggerated for convenience of illustration. Also, the number of glasses to be bonded is omitted.

In the step shown in FIG. 3A, the optical adhesive layer 325 is cured by irradiating the surfaces of the bonded translucent members 321 and 322 with ultraviolet rays in a direction substantially perpendicular thereto. Ultraviolet light passes through the dielectric multilayer film. In this embodiment, the polarization separation film 331 and the reflection film 332 are each formed of a dielectric multilayer film. Therefore, FIG.
By irradiating the surfaces of the translucent members 321 and 322 with ultraviolet rays in a direction substantially perpendicular to the surfaces, the plurality of optical adhesive layers 325 can be simultaneously cured.

On the other hand, when the reflection film 332 is formed by vapor deposition of aluminum, ultraviolet rays are reflected by the aluminum film. Therefore, in this case, as shown by a broken line in FIG. 3A, ultraviolet rays are irradiated on the surfaces of the light transmitting members 321 and 322 from a direction substantially parallel to the surfaces. At this time, the efficiency of irradiation of the optical adhesive layer 325 with the ultraviolet rays is reduced on the side opposite to the side where the ultraviolet rays are incident. Therefore, a relatively long time is required until the optical adhesive layer 325 is cured.
On the other hand, if the reflective film 332 is formed of a dielectric multilayer film, ultraviolet light can be irradiated from a direction that is not parallel to the surfaces of the translucent members 321 and 322, so that the optical adhesive layer 325 can be efficiently used in a relatively short time. Can be cured.

In the step of FIG. 3B, the plurality of translucent members 321 and 322 thus bonded to each other are substantially parallel to each other at a cut surface (indicated by a broken line in the drawing) forming a predetermined angle θ with the surface. The optical element block is cut out. The value of θ is preferably about 45 degrees. By polishing the surface (cut surface) of the optical element block thus cut out, a polarizing beam splitter array can be obtained.

FIG. 4 is a perspective view showing the polarizing beam splitter array 320 manufactured as described above. As can be seen from this figure, the polarizing beam splitter array 320
The first and second translucent members 321 and 322 each having a columnar shape having a parallelogram cross section are alternately bonded to each other.

FIG. 5A is a cross-sectional plan view showing a polarization conversion element in which a λ / 2 retardation plate 381 is selectively provided on a part of the exit surface of the polarization beam splitter array 320 according to the embodiment. FIG. 5B is a plan sectional view showing a polarization conversion element of a comparative example. In the polarization conversion element of the embodiment,
Of the emission surface (left surface in FIG. 5) of the polarization beam splitter array 320, a λ / 2 phase difference plate 381 as a polarization direction changing means is provided on the surface of the second translucent member 322.
Is affixed.

The structure of the comparative example shown in FIG.
In the configuration of the embodiment shown in FIG.
The only difference is that the positional relationship with the adjacent optical adhesive layer 325 is reversed. When manufacturing the polarizing beam splitter array 320a of the comparative example, first, the first
Forming a reflective film 332 on the surface of the light transmitting member 321;
On the other hand, the polarization separation film 3 is formed on the surface of the second light transmitting member 322.
31 are formed. And these translucent members 321,
322 are alternately stuck together with an optical adhesive layer 325.

From the incident surface of the polarization conversion device of the embodiment shown in FIG. 5A, incident light having a random polarization direction including an s-polarized component and a p-polarized component is incident. This incident light is first separated by the polarization separation film 331 into s-polarized light and p-polarized light. The s-polarized light is substantially vertically reflected by the polarization splitting film 331, further reflected by the reflection film 332, and emitted from the emission surface 326. On the other hand, p-polarized light
The light passes through the polarization splitting film 331 as it is, is converted into s-polarized light by the λ / 2 retardation plate 381, and is emitted. Therefore, only the s-polarized light is selectively emitted from the polarization conversion element.

If the λ / 2 retardation plate 381 is selectively provided on the exit surface of the first translucent member 321, only the p-polarized light can be selectively emitted from the polarization conversion element. Can be.

In the polarization beam splitter array 320 of the embodiment shown in FIG. 5A, the p-polarized light transmitted through the polarization splitting film 331 is applied between the entrance surface and the exit surface of the polarization beam splitter array 320 by an optical adhesive layer. One pass through 325. This is the same in the polarization beam splitter array 320a of the comparative example shown in FIG.

In the polarization beam splitter array 320 of the embodiment, the s-polarized light reflected by the polarization splitting film 331 travels once through the optical adhesive layer 325 between the entrance surface and the exit surface of the polarization beam splitter array 320. Also does not pass. On the other hand, in the polarization beam splitter array 320a of the comparative example, the s-polarized light is applied to the optical adhesive layer 3 between the entrance surface and the exit surface of the polarization beam splitter array 320.
Pass 25 twice. The optical adhesive layer 325 is substantially transparent, but has some light absorbing properties. Therefore, each time the light passes through the optical adhesive layer 325, the light amount decreases. Further, when passing through the optical adhesive layer 325, the polarization direction may be slightly changed. In the polarization beam splitter array of the embodiment, the number of times that the s-polarized light passes through the optical adhesive layer 325 is smaller than that of the comparative example, so that the light use efficiency is higher.

Incidentally, the polarizing beam splitter array 320a of the comparative example also has a smaller optical adhesive layer compared to the conventional polarizing beam splitter array 22 shown in FIG. However, it can be seen that the example shown in FIG. 5A has higher light use efficiency than the comparative example.

FIG. 10 is a cross-sectional view showing the polarizing beam splitter array 320 of the embodiment in further enlarged detail. The thicknesses of the polarization separation film 331 and the reflection film 332 are several μm, and the thicknesses t ₃₂₁ and t _{322 of the} translucent members ₃₂₁ and _322.
Also , it can be ignored compared to the thicknesses t _ad1 and t _ad2 of the optical adhesive layer 325. Therefore, in FIG. 10, the polarization separation film 331 is drawn by one broken line, and the reflection film 332 is drawn by one solid line. As described above, the polarization separation film 331 and the reflection film 332 are formed on both surfaces of the first light transmitting member 321. The thicknesses t _ad1 and t _ad2 of the optical adhesive layer 325 are
It may be set to a different value depending on the position of the layer,
Usually, the same value is set throughout the polarization beam splitter 320. In the following description, it is _assumed that the thicknesses t _ad1 and t _ad2 of the optical adhesive layer 325 are set to the same value t _ad .

As shown in the lower part of FIG. 10, the thickness t ₃₂₂ of the second light-transmitting member ₃₂₂ is equal to the thickness t ₃₂₁ of the first light-transmitting member 321 minus the thickness t _ad of the optical adhesive layer 325. Equal to the value minus the doubling. The same applies to the thickness (L ₃₂₁ , L ₃₂₂ , L _ad ) measured in the direction along the light exit surface 326 and the light entrance surface 327 of the polarizing beam splitter array 320. For example, the first translucent member 321
When the thickness t ₃₂₁ of the optical adhesive layer 325 is set to 3.17 mm, the thickness t _ad of the optical adhesive layer 325 is usually about 0.01 to 0.3.
mm, the thickness t ₃₂₂ of the second light transmitting member ₃₂₂ is in the range of 3.15 to 2.57 mm. As in this example, the thickness t ₃₂₂ of the second translucent member ₃₂₂ is
About 80% to about 9 of the thickness t ₃₂₁ of the first light transmitting member 321
It is preferably set to 0%. As a specific example,
t ₃₂₁ = 3.17 mm, t _ad = 0.06 mm, t ₃₂₂ =
It can be set to 3.05 mm.

As described above, the two types of translucent members 321 and
By adjusting the thickness of the polarization beam splitter 322 in advance, the distance between the polarization separation film 331 and the reflection film 332 after bonding can be made substantially uniform over the entire polarization beam splitter array 320.

Actually, the thicknesses t ₃₂₁ and t ₃₂₂ of the translucent members 321 and ₃₂₂ and the thickness t _ad of the optical adhesive layer 325 are shown.
May cause a manufacturing error.

FIG. 11 shows the polarization beam splitter array 3
A plurality of small lenses (condenser lenses) 3
Condenser lens array 31 in which 11 are arranged in a matrix
It is sectional drawing which shows the state which provided 0. On the light incident surface of the polarization beam splitter array 320, an effective incident area EA (light incident surface corresponding to the polarization separation film 331) on which light that enters the polarization separation film 331 and is converted into effective polarized light is incident.
And an invalid incident area UA (a light incident surface corresponding to the reflective film 332) on which the light that is incident on the reflective film 332 and converted into invalid polarized light is incident, are alternately arranged. The size Wp of the effective incident area EA and the invalid incident area UA in the x direction is one of the size WL of the condenser lens 311 in the x direction.
/ 2. The center (lens optical axis) 311c of the condenser lens 311 is disposed so as to be equal to the center of the effective incident area EA in the x direction. Effective incident area EA
Sets the polarization separation film 331 to the polarization beam splitter 320
Corresponds to the area projected on the light incident surface of the light emitting element. Therefore, the pitch of the polarization separation film 331 in the x direction is set to be equal to the pitch of the lens optical axis 311c of the condenser lens 311 in the x direction.

In the right end condenser lens 311 in FIG. 11, the corresponding polarization separation film 331 and reflection film 332 are not formed. This is because the amount of light passing through the condenser lens 311 at the end is relatively small, so that even if these films are not provided, the light use efficiency is not significantly affected.

FIG. 12 shows the pitch of the polarization separation film 331.
A value different from the pitch of the lens optical axis 311c of the condenser lens 311 is set, and the two polarization beam splitter arrays 320 'are arranged such that the polarization separation film 331 and the reflection film 332 face each other around the system optical axis L. It is explanatory drawing which shows the case where it arrange | positions facing. In the drawings, the portion on the left side of the system optical axis is omitted.

In the middle part of FIG.
The light intensity distribution of the light condensed by each of the 0 lenses La to Ld and irradiating the incident surface of the polarization beam splitter array 320 'is shown. In general, the light intensity Ia of light condensed by the lens La closest to the system optical axis (the center of the polarizing beam splitter array 320 ') is the strongest, and the light condensed by a lens farther from the optical axis is weaker, In FIG. 12, the light intensity Id of the light collected by the fourth lens Ld is the weakest. Further, the light amount distribution of the light condensed by each of the lenses La to Ld corresponds to a certain lens position (the third lens L in FIG. 12).
With respect to the position (c), the closer to the optical axis, the closer to the optical axis with respect to the lens center, and the farther from the optical axis, the closer to the optical axis. In FIG. 12, the light amount distribution Pc of the light condensed by the lens Lc is substantially distributed at the center of the lens, and
The closer to the optical axis, b and La, the light amount distributions Pb and Pa gradually become closer to the system optical axis. The light amount distribution Pd of the light condensed by the lens Ld is opposite to the system optical axis. In such a case, if the center of the effective incident area EA of the polarizing beam splitter array 320 ′ is made to uniformly coincide with the center of the lens optical axis, light loss occurs due to the above-described shift in the light amount distribution. In particular, a shift between the light amount distribution of light emitted from the lens array and the effective incident area EA near the optical axis of the light source causes a large light loss. Accordingly, each effective incident area of the polarizing beam splitter array 320 ′ is adjusted according to the distribution of the light emitted from the condenser lens array 310, that is, according to the peak interval of the light quantity distribution of the light emitted from the condenser lens array 310. It is preferable to arrange the centers of the EAs. In other words, the translucent member 32 is set such that the interval between the polarization separation films 331 matches the interval between the peaks of the light amount distribution.
1,322, thicknesses t ₃₂₁ , t ₃₂₂ and the optical adhesive layer 325
It is preferable to adjust the thickness t _ad (FIG. 10).

In order to more effectively use the light condensed by the lens array 310, it is preferable that light condensed by a lens closer to the optical axis be used more effectively. In particular, the amount of light near the light source optical axis is large,
Distribution Pa of light emitted from lens La near the light source optical axis
Is closer to the light source optical axis side than the center optical axis of the lens, the center of the effective incident area EA1 closest to the light source optical axis side of the polarizing beam splitter array 320 ′ is almost aligned with the peak position of the light distribution Pa. Is preferable.

The structure shown in FIG.
The widths of the effective incident areas EA1 to EA4 and the invalid incident areas UA1 to UA4 (that is, the intervals between the polarization separation films 311) correspond to the light intensity and the light amount distribution of the light emitted from each of the 10 condensing lenses 311. is there. That is, the effective incident area EA of the polarization beam splitter array 320 ′ (EA in the figure)
1 to EA4) and the invalid incident area UA (UA1 to U in the figure)
A4) The width Wp ′ in the x direction of the condensing lens array 310
Is larger than 1/2 of the width WL in the x direction of each of the lenses La to Ld.

In the example shown in FIG. 12, the polarizing beam splitter array 320 'is arranged so that the center of the lens Lc in the third row is equal to the center of the corresponding effective incident area EA3.
Is arranged. Usually, the width of each invalid incident area UA is
Since it is equal to the width Wp 'of the effective incident area EA, the two effective incident areas EA2 and EA1 on the left are gradually closer to the system optical axis with respect to the centers of the lenses Lb and La. Further, the rightmost effective incident area EA4 is opposite to the center of the lens Ld with respect to the system optical axis. As a result, each of the effective incident areas EA1 to EA4 substantially coincides with the peak position of the light amount distribution of the light emitted from the condenser lens array 310. In particular, since a predetermined number of lenses close to the optical axis, for example, two or three lenses, have a high light intensity, the light amount distribution of the light condensed by these lenses and the effective incident area corresponding thereto are almost equal. Preferably they match. With such a configuration, the light use efficiency can be further improved. It should be noted that how much the width of the effective incident area should be made larger than 1/2 of the width of the lens, and which lens should be arranged based on the effective incident area, depends on the number of lens arrays and each lens. It can be easily obtained experimentally from the relationship between the light quantity distributions. Further, the width of the effective incident area and the invalid incident area need not be limited to be larger than の of the width of the lens, and depends on the actual light amount distribution irradiating the light incident surface of the polarization beam splitter array 320 ′. It is determined.

In the examples shown in FIGS. 11 and 12, it is assumed that the small lenses 311 of the condenser lens array 310 have the same size. However, the size of the small lenses may be different depending on the position. FIG. 13 shows a condenser lens array 31 having a plurality of types of small lenses having different sizes.
It is the top view which shows 0 ', and its BB sectional drawing. FIG.
In FIG. 3A, a broken-line circle indicates an area where the light amount from the light source is relatively large.

The condensing lens array 310 ′ has a relatively small size first small lens 312 arranged in a matrix around the system optical axis L, and a relatively small size second small lens 313. Are arranged substantially in a matrix near the end of the condenser lens array 310 '. When achieving the same configuration and effect as in FIG. 11 described above for such a condensing lens array 310 ', the center of each effective incident area of the polarizing beam splitter array (that is, the pitch of the polarization splitting film). Are the corresponding small lenses 31
The light transmissive member 32 is adjusted to match the pitch of 2, 313.
1,322, thicknesses t ₃₂₁ , t ₃₂₂ and the optical adhesive layer 325
At least a part of the thickness t _ad (FIG. 10) is adjusted.
Alternatively, when achieving the same configuration and effect as in FIG. 12 described above, the center of each effective incident area of the polarization beam splitter array (that is, the pitch of the polarization splitting film) is shifted from the corresponding small lens 312, 313. The light-transmitting member 3 is adjusted to match the pitch of the light quantity distribution of the emitted light flux.
21, ₃₂₂ and thickness t ₃₂₁ , t ₃₂₂ and optical adhesive layer 32
At least a part of the thickness t _ad of _No. 5 is adjusted.

B. Second Embodiment: FIG. 14 to FIG.
FIG. 11 is an explanatory diagram illustrating a method for manufacturing the polarization beam splitter array according to the second embodiment. In the second embodiment, as shown in FIG. 14, an assembly jig 400 having a horizontal base 402 and a vertical wall 404 erected on the horizontal base 402 is used.

In the second embodiment, as in the first embodiment, the first light-transmitting member 321 (sheet glass on which a film is formed) and the second light-transmitting member shown in FIG. 322 (sheet glass on which a film is not formed) is prepared. Further, a dummy glass 324 shown in FIG. 14 is also prepared. This dummy glass 324 is a flat plate glass on which no polarization separation film or reflection film is formed. The dummy glass 324 is a member provided at an end of the polarization beam splitter, and the thickness thereof can be set to a value different from the thickness of the first and second light transmitting members 321 and 322.

In order to obtain the state shown in FIG. 14, first, the dummy glass 324 is placed on the horizontal base 402, and a photocurable adhesive is applied to the upper surface thereof. Then, the first light-transmitting member 321 is overlaid thereon. Thus, while the dummy glass 324 and the first light-transmitting member 321 stacked via the adhesive layer are rubbed, bubbles contained in the adhesive layer are expelled, and the thickness of the adhesive layer is made uniform. To In this state, the dummy glass 324 and the first translucent member 321 are in a state of being attracted to each other by surface tension. Then, as shown in FIG. 14, the side surfaces of the dummy glass 324 and the first light transmitting member 321 are
Contact 4 At this time, on the side surface perpendicular to the contacting side surface, the dummy glass 324 and the first translucent member 3 are disposed.
21 is shifted by a predetermined shift amount ΔH. FIG.
Then, ultraviolet light (indicated as “UV” in the figure) is irradiated from above the first light transmitting member 321 to cure the adhesive. The plate material thus bonded is referred to as a “first laminate”. In addition,
It is preferable that the ultraviolet light is irradiated from a direction that is not parallel to the surface of the translucent member 321. This makes it possible to efficiently irradiate the adhesive layer with ultraviolet light, thereby shortening the curing time of the adhesive. As a result, the throughput of manufacturing the optical element can be improved.

An adhesive is applied to the upper surface of the first laminate, and the second translucent member 322 is overlaid (FIG. 16). At this time, the first and second translucent members 32 overlapped with an adhesive layer interposed therebetween.
Air bubbles contained in the adhesive layer are expelled and the thickness of the adhesive layer is made uniform while sliding the 1,322. Further, the first light transmitting member 321 and the second light transmitting member 322 are shifted by a predetermined shift amount ΔH. In FIG. 17, ultraviolet light is irradiated from above the second translucent member 321 to cure the adhesive. Thus, a second laminate is obtained.

Thereafter, in the same manner, each time one translucent member is laminated via the adhesive layer, the adhesive layer is cured by irradiating it with ultraviolet rays.
The laminate shown in FIG. 18 is obtained. FIG. 19 shows a state in which the obtained laminate is cut. The laminate is
In FIG. 18, it is placed on the cutting table 410 with the side that has contacted the vertical wall 404 facing down. Then, it is cut along parallel cutting lines 328a and 328b. Thereafter, the cut surface is polished flat to obtain an element similar to the polarization beam splitter array of the first embodiment shown in FIG. However, the polarizing beam splitter array created in the second embodiment has a dummy glass 32 at the end.
4 are provided.

In the second embodiment, the adhesive layer is cured by irradiating ultraviolet rays each time one translucent member is laminated via the adhesive layer. The positional relationship between them can be determined with high accuracy.
In addition, since only one adhesive layer needs to be cured by ultraviolet irradiation, there is an advantage that the curing can be surely performed. Note that the polarizing beam splitter array of the first embodiment can be assembled by the assembling method of the second embodiment.

Incidentally, by the same steps as in the second embodiment,
A plurality of laminates (referred to as “unit laminates”) obtained by laminating one first translucent member 321 and one second translucent member 322 are created in advance. ,
These unit laminates may be sequentially laminated.
That is, one unit laminate may be laminated via the adhesive layer to expel air bubbles from the adhesive layer, and thereafter, the adhesive layer may be cured by irradiating ultraviolet rays. With such a process, substantially the same effects as described above can be obtained.

In any of the first to third embodiments, the accuracy of the thickness of the light transmitting members 321 and 322 can be controlled when polishing the respective surfaces. Further, the thickness of the adhesive layer can be made uniform by making the amount of the adhesive applied and the pressure in the bubble removing step uniform over the surface of the member.

C. Configuration of Polarized Lighting Apparatus and Image Display Apparatus: FIG. 6 is a schematic structural view of a main part of a polarized light illuminating apparatus 1 having a polarizing beam splitter array according to the above-described embodiment as viewed in plan. The polarized light device 1 includes a light source unit 10
And a polarization generator 20. The light source unit 10
A light beam having a random polarization direction including an s-polarized component and a p-polarized component is emitted. The light beam emitted from the light source unit 10 is converted by the polarization generator 20 into one type of linearly polarized light whose polarization direction is substantially uniform, and illuminates the illumination area 90.

The light source section 10 includes a light source lamp 101 and a parabolic reflector 102. Light source lamp 10
The light radiated from 1 is reflected in one direction by the parabolic reflector 102, becomes a substantially parallel light flux, and enters the polarization generator 20. The light source optical axis R of the light source unit 10 is in a state shifted in parallel to the X direction by a fixed distance D with respect to the system optical axis L. Here, the system optical axis L is the optical axis of the polarization beam splitter array 320. The reason for shifting the light source optical axis R in this manner will be described later.

The polarization generator 20 is provided with a first optical element 20.
0 and a second optical element 300. FIG.
FIG. 2 is a perspective view illustrating an appearance of a first optical element 200. FIG.
As shown in (1), the first optical element 200 has a configuration in which a plurality of minute light beam splitting lenses 201 having a rectangular outline are arranged vertically and horizontally. The first optical element 200 is arranged such that the light source optical axis R (FIG. 6) coincides with the center of the first optical element 200. Each light beam splitting lens 201 is Z
The external shape viewed from the direction is set to be similar to the shape of the illumination area 90. In the present embodiment, since the horizontally long illumination region 90 is assumed in the X direction, the outer shape of the light beam splitting lens 201 on the XY plane is also horizontally long.

The second optical element 300 in FIG. 6 includes a condensing lens array 310 and a polarizing beam splitter array 320
, A selective retardation plate 380, and an emission-side lens 390. As described with reference to FIG. 5, the selective phase difference plate 380 has the λ / 2 phase difference plate 381 formed only on the emission surface portion of the second light transmitting member 322, and the first light transmitting member 3
The exit surface portion 21 is a plate-like body that is colorless and transparent. In the polarization beam splitter array shown in FIG. 6, the protruding portions at both ends of the structure shown in FIG. 4 are cut to have a substantially rectangular parallelepiped shape.

The condenser lens array 310 has substantially the same configuration as the first optical element 200 shown in FIG. That is, the condensing lens array 310 includes the first optical element 2
A plurality of condensing lenses 311 of the same number as the light beam splitting lens 201 constituting 00 are arranged in a matrix.
The center of the condenser lens array 310 is also arranged so as to coincide with the light source optical axis R.

The light source unit 10 emits a substantially parallel white light beam having a random polarization direction. A light beam emitted from the light source unit 10 and incident on the first optical element 200 is split into an intermediate light beam 202 by each light beam splitting lens 201. The intermediate light beam 202 is a light beam splitting lens 201
And the light condensing function of the light condensing lens 311 converges in a plane perpendicular to the system optical axis L (XY plane in FIG. 1). At the position where the intermediate light beam 202 converges, the light beam splitting lens 20
As many light source images as the number of light source images are formed. The position where the light source image is formed is near the polarization separation film 331 in the polarization beam splitter array 320.

The reason why the light source optical axis R is shifted from the system optical axis L is to form a light source image at the position of the polarization separation film 331. This shift amount D is set to の of the width Wp (FIG. 6) of the polarization separation film 331 in the X direction. As described above, the centers of the light source unit 10, the first optical element 200, and the condenser lens array 310 coincide with the light source optical axis R, and are shifted from the system optical axis L by D = Wp / 2. I have. On the other hand, as can be understood from FIG.
The center of the polarization separation film 331 that separates
By Wp / 2. Therefore, the light source optical axis R is
By deviating from the system optical axis L by Wp / 2, the light source lamp 1 is almost at the center of the polarization separation film 331.
01 light source image can be formed.

The light beam incident on the polarizing beam splitter array 320 is, as shown in FIG.
All are converted to s-polarized light. The light beam emitted from the polarization beam splitter array 320 illuminates the illumination area 90 with the emission side lens 390. Since the illumination area 90 is illuminated with a large number of light beams split by the many light beam splitting lenses 201, the entire illumination area 90 can be evenly illuminated.

When the parallelism of the light beam incident on the first optical element 200 is extremely good, the second optical element 30
It is also possible to omit the condenser lens array 310 from 0.

As described above, the polarized light illumination device 1 shown in FIG.
Has a function as a polarization generator for converting a white light beam having a random polarization direction into a light beam having a specific polarization direction (s-polarized light or p-polarized light), and the illumination region 90 is not unevenly distributed by such a large number of polarized light beams. Lighting function. Since the polarized light illuminating device 1 uses the polarized beam splitter array 320 according to the embodiment, the polarized light illuminating device 1 has an advantage that the light use efficiency is higher than in the related art.

FIG. 8 is a schematic configuration diagram showing a main part of a projection display device 800 provided with the polarized light illumination device 1 shown in FIG. The projection display device 800 includes a polarized light illumination device 1 and
Dichroic mirrors 801 and 804 and reflection mirror 8
02, 807, 809 and relay lenses 806, 80
8,810 and 3 liquid crystal panels (liquid crystal light valve)
803, 805, 811; a cross dichroic prism 813; and a projection lens 814.

The dichroic mirrors 801 and 804 are
It has a function as a color light separating unit that separates a white light beam into three color lights of red, blue and green. Three liquid crystal panels 803
Reference numerals 805 and 811 each have a function as a light modulation unit that modulates three color lights to form an image according to given image information (image signal). The cross dichroic prism 813 has a function as a color light combining unit that forms a color image by combining three color lights. The projection lens 814 has a function as a projection optical system that projects light representing a synthesized color image on a screen 815.

A blue light green light reflecting dichroic mirror 801
Transmits the red light component of the white light beam emitted from the polarized light illuminating device 1 and reflects the blue light component and the green light component. The transmitted red light is reflected by the reflection mirror 802 and reaches the red light liquid crystal panel 803. Meanwhile, the first
Of the blue light and green light reflected by the dichroic mirror 801, the green light is reflected by the green light reflecting dichroic mirror 804 and reaches the green light liquid crystal panel 805. On the other hand, the blue light is transmitted to the second dichroic mirror 8.
04 is also transmitted.

In this embodiment, the optical path length of the blue light is the longest of the three color lights. Therefore, for blue light, after the dichroic mirror 804, the incident lens 8
, A light guide unit 850 configured by a relay lens system including a relay lens 808, and an emission lens 810. That is, after transmitting the blue light through the green light reflecting dichroic mirror 804, first, the incident lens 8
06 and the reflection mirror 807, the relay lens 808
It is led to. Further, the light is reflected by the reflection mirror 809 and guided to the emission lens 810, and the liquid crystal panel 81 for blue light is reflected.
Reach one. The three liquid crystal panels 803, 805,
Reference numeral 811 corresponds to the illumination area 90 in FIG.

The three liquid crystal panels 803, 805, 811
Modulates each color light according to an image signal (image information) provided from an external control circuit (not shown), and generates color light including image information of each color component. The modulated three color lights are cross-dichroic prism 81
3 is incident. In the cross dichroic prism 813, a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape. The three color lights are combined by these dielectric multilayer films to form light representing a color image. The synthesized light is projected on a screen 815 by a projection lens 814 as a projection optical system, and an image is displayed in an enlarged manner.

In the projection display device 800, liquid crystal panels 803, 805, and 8 of a type that modulates a light beam (s-polarized light or p-polarized light) in a specific polarization direction as light modulating means.
11 is used. Generally, a polarizing plate (not shown) is attached to each of the liquid crystal panels on the incident side and the output side. Therefore, when the liquid crystal panel is irradiated with a light beam having a random polarization direction, about half of the light beam is absorbed by the polarizing plate of the liquid crystal panel and turned into heat. As a result, light utilization efficiency is low, and
There is a problem that the polarizing plate generates heat. However, in the projection display device 800 shown in FIG. 8, since the polarized light illuminating device 1 generates a light beam of a specific polarization direction passing through the liquid crystal panels 803, 805, and 811, the light of the light in the polarizing plate of the liquid crystal panel is generated. The problem of absorption and fever has been greatly improved. Further, since the projection display device 800 uses the polarization beam splitter array 320 according to the embodiment, there is an advantage that the light use efficiency of the entire projection display device 800 is enhanced by this.

The polarization beam splitter array 320
The reflection film 332 of the liquid crystal panel 803, 805, 811
It is preferable to form a dielectric multilayer film having a property of selectively reflecting only a specific polarization component (for example, s-polarized light) to be modulated. In this case, the liquid crystal panels 803, 8
The problems of light absorption and heat generation in 05 and 811 can be further improved. As a result, the light use efficiency of the entire projection display device 80 can be further increased.

As described above, by using the polarizing beam splitter array according to this embodiment, the light use efficiency of the projection display device can be increased as compared with the conventional case. Therefore, the image projected on the screen 815 can be made brighter.

It should be noted that the present invention is not limited to the above-described examples and embodiments, but can be carried out in various modes without departing from the gist of the present invention.
For example, the following modifications are possible.

(1) The polarizing beam splitter array according to the present invention is not limited to the projection type display device shown in FIG. 8, and can be applied to various other devices. For example,
The polarizing beam splitter array according to the present invention can be applied to a projection display device that projects a black and white image instead of a color image. In this case, in the device of FIG.
Only one liquid crystal panel is required, and the color light separating means for separating light beams into three colors and the color light combining means for combining light beams of three colors can be omitted.

(2) In the embodiment shown in FIG. 5, a light shielding means for preventing light from entering from the incident surface of the second light transmitting member may be provided. FIG. 9 (A) shows the state shown in FIG.
FIG. 13 is an explanatory diagram showing a state where a light shielding plate 340 is provided in front of the optical element of the embodiment shown in FIG. This light shielding plate 34
At 0, light-shielding portions 341 that block light and light-transmitting portions 342 that transmit light are formed alternately. The light-shielding plate 340 is provided on a surface of a light-transmitting plate material such as a glass plate, for example.
The light shielding portion 341 is formed by forming a light reflection film or an absorption film. The light shielding portion 341 is configured to shield the incident surface 32 of the second translucent member 322 so as to shield the incident surface 327.
7 are provided.

FIG. 9B shows an optical path of light incident on the incident surface 327 of the second light transmitting member 322 when the light shielding plate 340 is not provided. Incident surface 32
7, after being reflected by the reflective film 332a,
The light is separated into s-polarized light and p-polarized light by the separation film 331 thereabove. The p-polarized light is converted to s-polarized light by the λ / 2 retardation plate 381. On the other hand, the s-polarized light is reflected by the upper reflective film 332b and exits from the exit surface 326. As can be seen from FIG. 9B, the s-polarized light component of the light incident from the incident surface 327 is
The first optical adhesive layer 325a passes twice before reaching the upper reflective film 332b, and the next optical adhesive layer 325a.
b once. On the other hand, the p-polarized light component reaches the two optical adhesive layers
a and 325b each twice. As described above, when the light shielding plate 340 is not provided, light incident on the incident surface 327 of the second light transmitting member 322 passes through the optical adhesive layer 325 many times. Therefore, FIG.
By providing the light-shielding plate 340 as shown in (A), such light can be shielded.

Instead of providing the light-shielding plate 340 separately from the polarization beam splitter array 320, a light-shielding part 341 is formed on the incident surface 327 of the second light-transmissive member 322 using a reflective film made of aluminum or the like. You may do so.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a polarization conversion element.

FIG. 2 is a process cross-sectional view showing main processes for manufacturing a polarizing beam splitter array according to an embodiment of the present invention.

FIG. 3 is a process cross-sectional view showing main processes for manufacturing a polarizing beam splitter array according to an embodiment of the present invention.

FIG. 4 shows a polarizing beam splitter array 32 according to an embodiment.
FIG.

FIG. 5 is a cross-sectional plan view showing a polarization conversion element of an example and a comparative example in comparison.

FIG. 6 is a schematic configuration diagram of a main part of a polarized light illuminating device having a polarized beam splitter array according to an embodiment, as viewed in plan.

FIG. 7 is a perspective view showing an appearance of a first optical element 200.

FIG. 8 is a projection display device 800 including the polarized light illumination device 1.
The schematic block diagram which showed the principal part of FIG.

FIG. 9 is an explanatory diagram showing a configuration of an optical element having a light shielding plate 340.

FIG. 10 shows a polarizing beam splitter array 320 according to an embodiment.
Sectional drawing which expands and shows in detail.

FIG. 11 is a sectional view showing a state in which a condensing lens array 310 in which a plurality of small lenses (condensing lenses) 311 are arranged in a matrix on the light incident surface side of a polarizing beam splitter array 320;

FIG. 12 shows the pitch of the polarization splitting film 331,
FIG. 11 is an explanatory diagram showing a case where a pitch different from the pitch of the eleventh lens optical axis 311c is set.

FIG. 13 is a plan view showing a condenser lens array 310 ′ having a plurality of types of small lenses having different sizes, and FIG.
B sectional drawing.

FIG. 14 is an explanatory view showing a method for manufacturing a polarization beam splitter array in the second embodiment.

FIG. 15 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment.

FIG. 16 is an explanatory diagram showing a method for manufacturing a polarization beam splitter array in the second embodiment.

FIG. 17 is an explanatory view showing a method of manufacturing the polarization beam splitter array in the second embodiment.

FIG. 18 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment.

FIG. 19 is an explanatory view showing a method for manufacturing a polarization beam splitter array in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Polarization illumination device 10 ... Light source part 20 ... Polarization generator 22 ... Polarization beam splitter array 30 ... Polarization beam splitter 32,34,42,44 ... Right angle prism 36 ... Polarization separation film 40 ... Prism 46 ... Reflection film 80 ... Projection Type display device 90 Illumination area 101 Light source lamp 102 Parabolic reflector 200 First optical element 201 Light beam splitting lens 202 Intermediate light beam 300 Second optical element 310 Condenser lens array 311 Condenser Lens 320 Polarized beam splitter array 321 First translucent member 322 Second translucent member 325 Optical adhesive layer 326 Outgoing surface 327 Entrance surface 331 Polarized light separating film 332 Reflective film 340 Shielding plate 341 Shielding part 342 Translucent part 380 Selected phase plate 381 λ / 2 phase plate 390 Emitter lens 800 Projection display device 801 Blue light / green light reflecting dichroic mirror 802, 807, 809 Reflecting mirror 803, 805, 811 Liquid crystal panel 804 Green light reflecting dichroic mirror 806 ... Incident lens 807 ... Reflecting mirror 808 ... Relay Lens 809 ... Reflection mirror 810 ... Emission lens 813 ... Cross dichroic prism 814 ... Projection lens 815 ... Screen 850 ... Light guide means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/31 H04N 9/31 BC

Claims (20)

[Claims] 1. An optical element, comprising: a light incident surface; and a light exit surface substantially parallel to the light incident surface, and formed to form a predetermined angle with the light incident surface and the light exit surface. First and second film formation surfaces substantially parallel to each other, and a polarization separation film formed on the first film formation surface;
A plurality of first translucent members each including a reflective film formed on the second film forming surface; and a plurality of the first translucent members alternately bonded to the plurality of first translucent members. A plurality of second translucent members each having a light incident surface and a light exit surface formed on the same plane as the light incident surface and the light exit surface of the one light transmissive member. Optical element. 2. The optical element according to claim 1, wherein the reflection film is formed of a dielectric multilayer film. 3. The optical element according to claim 1, further comprising: a light-emitting surface of the first light-transmitting member or a light-emitting surface of the second light-transmitting member. An optical element comprising a correspondingly provided polarization direction changing means. 4. The optical element according to claim 1, further comprising a light blocking unit provided corresponding to the light incident surface of the second light transmitting member. 5. The optical element according to claim 1, wherein an adhesive layer is provided on a boundary surface between the first and second translucent members. At least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is such that the distance between the polarization separation film and the reflection film is substantially equal through the optical element. The optical element that is set. 6. The optical element according to claim 5, wherein a thickness of the second light transmitting member is set smaller than a thickness of the first light transmitting member. 7. The optical element according to claim 6, wherein the thickness of the second light transmitting member is in a range from about 80% to about 90% of the thickness of the first light transmitting member. , Optical elements. 8. The optical element according to claim 5, wherein the thickness of the first light transmitting member is equal to the thickness of the second light transmitting member. An optical element substantially equal to a value obtained by adding twice the thickness of the layer. 9. The optical element according to claim 1, wherein the optical element is used together with a plurality of small lenses arranged on a light incident surface side of the optical element. An optical element, wherein an interval between the plurality of polarization split films in the optical element is set to substantially correspond to a pitch of the plurality of small lenses. 10. The optical element according to claim 9, further comprising: an adhesive layer on a boundary surface between the first and second light-transmissive members. At least a part of the thickness of the first and second light-transmissive members and the thickness of the adhesive layer is such that the mutual interval substantially corresponds to the pitch of the lens optical axes of the plurality of small lenses. The optical element that is set. 11. The optical element according to claim 10, wherein the plurality of small lenses have a plurality of different lens optical axis pitches, and a distance between the plurality of polarization separation films is equal to the plurality of polarization separation films. An optical element, wherein at least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is set so as to substantially correspond to different lens optical axis pitches. 12. The optical element according to claim 1, wherein the optical element is used together with a plurality of small lenses arranged on a light incident surface side of the optical element. An optical element, wherein an interval between the plurality of polarization split films in the optical element is set to substantially correspond to a pitch of a plurality of light beams emitted from the plurality of small lenses. 13. The optical element according to claim 12, further comprising: an adhesive layer on a boundary surface between the first and second light-transmitting members. At least one of the thickness of the first and second light-transmissive members and the thickness of the adhesive layer so that a mutual interval substantially corresponds to a pitch of a plurality of light beams emitted from the plurality of small lenses. Some are set,
Optical element. 14. A method for manufacturing an optical element, comprising: (a)
Forming a polarization separation film on the first surface of the first light-transmitting plate having substantially parallel first and second surfaces; and (b) forming a first light-transmitting plate of the first light-transmitting plate. Forming a reflective film on the surface of (2); (c) a plurality of the first translucent plate members on which the polarized light separating film and the reflective film are formed;
Alternately laminating a plurality of second translucent plate members each having two substantially parallel surfaces, and (d) attaching the alternately translucent plate materials to the first and second surfaces. Producing an optical element block having a substantially parallel light entrance surface and a light exit surface by cutting at a predetermined angle with respect to the optical element block. 15. The method of manufacturing an optical element according to claim 14, further comprising: (e) polishing the light incident surface and the light output surface of the optical element block. Method. 16. The method for manufacturing an optical element according to claim 14, wherein the step (c) comprises a plurality of the first light-transmitting plate members and a plurality of the second light-transmitting plate materials. A method of manufacturing an optical element, comprising: a step of alternately laminating a plate material with a photocurable adhesive layer via a light-curable adhesive layer and bonding them by light irradiation. 17. The method for manufacturing an optical element according to claim 14, wherein the step (c) comprises: (1) one piece of the first light-transmissive member and one piece of the one light-transmitting member. A step of forming a laminate by overlapping with a second translucent member via a photocurable adhesive layer; and (2) irradiating the laminate with light to form the photocurable adhesive layer. And (3) alternately stacking the first light-transmissive member and the second light-transmissive member on the laminate via the photocurable adhesive layer, A step of irradiating the laminated body with light each time one member is stacked to cure the photocurable adhesive layer. 18. The method for manufacturing an optical element according to claim 14, wherein the step (c) comprises: (1) one piece of the first light-transmitting member and one piece of the one light-transmitting member. A step of forming a laminate by overlapping with a second translucent member via a photocurable adhesive layer; and (2) irradiating the laminate with light to form the photocurable adhesive layer. And (3) alternately stacking the plurality of laminates created in the steps (1) and (2) via the photocurable adhesive layer,
At this time, a step of curing the photocurable adhesive layer by irradiating light each time one laminated body is stacked is provided. 19. The method for manufacturing an optical element according to claim 16, wherein the light irradiation is performed from a direction not parallel to a surface of the light transmitting member. Method. 20. An optical element according to claim 1, wherein the light is emitted from the optical element into one type of polarized light, and the light is emitted from the polarization converting means. A projection display apparatus comprising: a modulation unit that modulates emitted light based on a given image signal; and a projection optical system that projects a light beam modulated by the modulation unit.