JP2004110053A - Method for manufacturing optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent loss of light and to improve the utilization efficiency of light in a polarized light conversion element. <P>SOLUTION: First and second translucent members 321, 322 which are respectively formed like plates are prepared. The first translucent member 321 has first and second surfaces (film forming surfaces) which are almost parallel with each other. A polarized light separating film 331 is formed on the first film forming surface, and a reflection film 332 is formed on the second film forming surface. These films are not formed on the surface of the second translucent member 322. Then a plurality of first translucent members 321 and a plurality of second translucent members 322 are alternately stuck to each other. The stuck translucent member is cut off at a prescribed angle with respect to the surface and the cut surface is polished to form a polarized beam splitter array 320. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an optical element, a manufacturing method therefor, and a projection display device including the optical element.

As an optical element (polarization conversion element) that converts light having a random polarization direction into light having a single polarization direction, one described in JP-A-7-294906 is known. 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 λ / 2 retardation plate 24 is selectively provided on a part of the exit surface of the polarization beam splitter array 22.

The -linear polarization beam splitter 30 has two right-angle prisms 32 and 34 and a polarization separation film 36 formed on a boundary surface that is a slope of the right-angle prisms 32 and 34. 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 bonded with an optical adhesive.

The -line 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 the prism 40, the reflection film 46 is formed on the slope of one of the right-angle prisms, and then 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.

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

入射 From the light incident surface, incident light containing 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 separation 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, is converted into s-polarized light by the λ / 2 retardation plate 24, and is emitted. Therefore, light beams having a random polarization direction incident on the optical element are all emitted as s-polarized light beams.

で は In the conventional optical element shown in FIG. 1, four right-angle prisms 32, 34, 42, and 44 are bonded to each other with an optical adhesive. Therefore, the s-polarized light and the p-polarized light must pass through the optical adhesive layer formed on the boundary of the prism many times between the time when the light is incident on the optical element and the time when the light is emitted. 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.

The present invention has been made in order to solve the above-mentioned problems in the conventional technology, and has as its object to provide a technology capable of increasing the efficiency of using light in an optical element.

In order to solve at least a part of the problems described above, a first invention is an optical element,
First and second substantially parallel films having a light incident surface and a light exit surface substantially parallel to the light incident surface, and formed at a predetermined angle with the light incident surface and the light exit surface. A plurality of first light-transmissive members each including a forming surface, a polarization separating film formed on the first film forming surface, and a reflecting film formed on the second film forming surface; ,
A light incident surface and a light exit surface that are alternately bonded to the plurality of first light transmissive members and are respectively formed on the same plane as the light incident surface and the light exit surface of the plurality of first light transmissive members. A plurality of second translucent members each having
It is characterized by having.

According to the first invention, of the light incident from the light incident surface of the first light transmitting member, the polarized light component reflected by the polarization separation film is reflected by the reflection film without passing through the optical adhesive layer. It is reflected and then exits the polarizing beam splitter. Therefore, the number of times that this polarized light component passes through the optical adhesive layer can be reduced, so that the light use efficiency can be increased.

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

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

In the first aspect, the apparatus further includes a polarization direction conversion unit provided corresponding to the light exit surface of the first light transmissive member or the light exit surface of the second light transmissive member. Is preferred.

(4) 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.

に お い て In the first invention, it is preferable that a light-shielding unit is further provided corresponding to the light incident surface of the second light-transmitting member.

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

Further, in the first invention,
An adhesive layer is provided on an interface between the first and second translucent members, respectively.
At least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is set so that the distance between the polarization splitting film and the reflection film is substantially equal through the optical element. It is preferred that

(4) 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.

Further, in the first invention,
It is preferable that the thickness of the second translucent member is set smaller than the thickness of the first translucent member. In this case, the distance between the polarization separation film and the reflection film can be made equal, and the light use efficiency of the optical element can be improved.

The thickness of the second light transmitting member is preferably in the range of about 80% to about 90% of the thickness of the first light transmitting member.

Preferably, the thickness of the first light-transmitting member is substantially equal to a value obtained by adding twice the thickness of the adhesive layer to the thickness of the second light-transmitting member.

Further, the optical element is an optical element used with a plurality of small lenses arranged on the light incident surface side of the optical element,
It is preferable that an interval between the plurality of polarization split films in the optical element is set so as to substantially correspond to a 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, respectively, so that the light use efficiency is improved.

As an example, each has an adhesive layer on a boundary surface between the first and second light-transmitting members,
The thickness of the first and second light-transmissive members and the thickness of the adhesive layer such that the interval between the plurality of polarization separation films substantially corresponds to the pitch of the lens optical axes of the plurality of small lenses. Is set at least in part.

Alternatively, the plurality of small lenses have a plurality of different lens optical axis pitches,
The distance between the plurality of polarized light separating films is substantially equal to the plurality of different lens optical axis pitches, and the distance between the thickness of the first and second translucent members and the thickness of the adhesive layer is selected. Is preferably set at least in part.

With this configuration, even when the pitch of the lens optical axes is different, 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. .

Further, in the first aspect, the optical element is an optical element used together with a plurality of small lenses arranged on a light incident surface side of the optical element,
It is preferable that 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.

ピ ッ チ The pitch of the light beam emitted from the small lens does not always match 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, each has an adhesive layer on a boundary surface between the first and second light-transmitting members,
The thickness of the first and second translucent members and the thickness of the adhesive layer such that the interval between the plurality of polarization separation films substantially corresponds to the pitch of the plurality of light beams emitted from the plurality of small lenses. At least a part of the thickness is set.

A second invention is a method for manufacturing an optical element,
(A) forming a polarization splitting film on the first surface of a first light-transmitting plate having substantially parallel first and second surfaces;
(B) forming a reflective film on the second surface of the first translucent plate;
(C) The plurality of first light-transmitting plate members on which the polarization separation film and the reflection film are formed, and the plurality of second light-transmitting plate members having two substantially parallel surfaces are alternately bonded to each other. Process and
(D) cutting the translucent plate members alternately bonded to each other at a predetermined angle with respect to the first and second surfaces to form an optical element block having a light incidence surface and a light emission surface which are substantially parallel to each other; Generating,
It is characterized by having.

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 above second invention, further,
(E) polishing the light incident surface and the light exit surface of the optical element block;
It is preferable to provide

れ ば Thus, the light incident surface and the light exit surface of the optical element block serving as the optical element can be easily polished, so that the optical element can be easily manufactured.

In the second invention,
The step (c) is 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;
It is preferable to provide

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

Alternatively, the step (c) comprises:
(1) forming a laminate by laminating one sheet of the first translucent member and one sheet of the second translucent member via a photocurable adhesive layer; ,
(2) curing the photocurable adhesive layer by irradiating the laminate with light;
(3) The first light-transmissive member and the second light-transmissive member are alternately stacked on the laminate via the photocurable adhesive layer. A step of curing the photocurable adhesive layer by irradiating the laminate with light each time it is stacked,
May be provided.

In this case, the adhesive is cured each time one translucent member is stacked, so that the positional relationship between the translucent members can be accurately set.

Alternatively, the step (c) comprises:
(1) forming a laminate by laminating one sheet of the first translucent member and one sheet of the second translucent member via a photocurable adhesive layer; ,
(2) curing the photocurable adhesive layer by irradiating the laminate with light;
(3) The plurality of laminates created in the steps (1) and (2) are alternately stacked via the photocurable adhesive layer. In this case, each time one laminate is stacked Curing the photocurable adhesive layer by irradiating light,
May be provided.

(4) According to this method, the adhesive is cured each time one laminated body is stacked, so that the positional relationship between the adjacent translucent members can be accurately set.

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

In this case, since the adhesive is efficiently irradiated with the 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, comprising: any one of the above optical elements;
Polarization conversion means for converting the light emitted from the optical element to one type of polarized light,
Modulation means for modulating the light emitted from the polarization conversion means based on a given image signal,
A projection optical system for projecting the light beam modulated by the modulation means.

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.

A. First embodiment:
Next, embodiments of the present invention will be described based on examples. 2 and 3 are sectional views showing main steps of 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.

板 Sheet glass is used for the first and second translucent members 321 and 322. However, a translucent plate material other than glass can be used. Alternatively, one of the first and second translucent members may be made of a material having a different color from the other. In this way, 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 may be formed of a colorless transparent plate glass and the other may be formed of a blue transparent plate glass. As the sheet glass, polished sheet glass or float glass is preferable, and particularly, polished sheet glass is preferable.

The polarization separation 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 331 is formed by stacking dielectric multilayer films having such properties.

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. The reflection film 332 is formed of 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. Are preferred.

The reflective 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 reflection film 332 is formed of a dielectric multilayer film, the amount of light emitted from the polarization beam splitter array can be increased. Furthermore, 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, it is necessary to improve the reflectivity of each film constituting the dielectric multilayer film (usually a structure in which two types of films are alternately laminated) constituting the reflection film 332. The thickness or the material of the film may be optimized.

(2) In the step of 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 between the reflection film 332 and the second light transmitting 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.

(3) In the step of 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 to the surfaces. 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, as shown in FIG. 3A, the plurality of optical adhesive layers 325 can be cured at the same time by irradiating the surfaces of the translucent members 321 and 322 with ultraviolet rays from a direction substantially perpendicular thereto.

On the other hand, when the reflective film 332 is formed by vapor deposition of aluminum, ultraviolet rays are reflected by the aluminum film. Therefore, in this case, as shown by the broken line in FIG. 3A, the ultraviolet rays are applied to the surfaces of the translucent members 321 and 322 in 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 at the portion 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 reflection 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 light-transmitting members 321 and 322 thus bonded to each other are cut substantially parallel to a cut surface (indicated by a broken line in the drawing) forming a predetermined angle θ with the surface. Thereby, 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 thus manufactured. As can be seen from this figure, the polarizing beam splitter array 320 has a shape in which first and second translucent members 321 and 322 each having a columnar shape having a parallelogram cross section are alternately bonded.

FIG. 5A is a cross-sectional plan view showing a polarization conversion element in which a λ / 2 phase difference plate 381 is selectively provided on a part of an emission 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 exit surface (the left surface in FIG. 5) of the polarization beam splitter array 320, the surface portion of the second translucent member 322 is provided with λ / 2 as polarization direction conversion means. A phase difference plate 381 is attached.

The configuration of the comparative example shown in FIG. 5B is different from the configuration of the example of FIG. 5A in that the positional relationship between the polarization separation film 331 and the optical adhesive layer 325 adjacent thereto is reversed. Only differ. When manufacturing the polarizing beam splitter array 320a of the comparative example, first, the reflection film 332 is formed on the surface of the first light-transmitting member 321 and, on the other hand, on the surface of the second light-transmitting member 322. The polarization separation film 331 is formed. Then, the light-transmissive members 321 and 322 are alternately bonded with the optical adhesive layer 325.

(5) Incident light having a random polarization direction including an s-polarized light component and a p-polarized light component is incident from the incident surface of the polarization conversion element of the embodiment shown in FIG. 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 reflected almost vertically by the polarization separation film 331, further reflected by the reflection film 332, and emitted from the emission surface 326. On the other hand, the p-polarized light passes through the polarization separation 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.

In the polarization beam splitter array 320 of the embodiment shown in FIG. 5A, the p-polarized light transmitted through the polarization separation film 331 has one optical adhesive layer 325 between the entrance surface and the exit surface of the polarization beam splitter array 320. Pass twice. This is the same in the polarization beam splitter array 320a of the comparative example shown in FIG.

Further, in the polarization beam splitter array 320 of the embodiment, the s-polarized light reflected by the polarization separation film 331 does not pass through the optical adhesive layer 325 at least once between the entrance surface and the exit surface of the polarization beam splitter array 320. . On the other hand, in the polarization beam splitter array 320a of the comparative example, the s-polarized light passes through the optical adhesive layer 325 twice between the entrance surface and the exit surface of the polarization beam splitter array 320. 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. 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.

By the way, 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 polarization 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 can be ignored compared to the thicknesses t ₃₂₁ and t _{322 of} the light transmitting members 321 and ₃₂₂ and 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 may be set to different values depending on the position of the layer, but are usually set to the same value 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 translucent member 322 is obtained by subtracting twice the thickness t _ad of the optical adhesive layer 325 from the thickness t _{321 of} the first translucent member 321. Equal to 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 incident surface 327 of the polarizing beam splitter array 320. For example, when the thickness t ₃₂₁ of the first translucent member 321 is set to 3.17 mm, the thickness t _ad of the optical adhesive layer 325 is usually in the range of about 0.01 to 0.3 mm. The thickness t322 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 light transmitting member 322 is preferably about 80% to about 90% of the thickness t ₃₂₁ of the first light transmitting member 321. As a specific example, t ₃₂₁ = 3.17 mm, t _ad = 0.06 mm, and t ₃₂₂ = 3.05 mm can be set.

As described above, by adjusting the thicknesses of the two types of translucent members 321 and 322 in advance, the distance between the polarization separation film 331 and the reflection film 332 after the bonding is adjusted. Can be made substantially uniform over the entire area.

Actually, manufacturing errors may occur in the thicknesses t ₃₂₁ and t ₃₂₂ of the translucent members 321 and ₃₂₂ and in the thickness t _ad of the optical adhesive layer 325.

FIG. 11 is a cross-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 is provided on the light incident surface side of the polarizing beam splitter array 320. The light incident surface of the polarization beam splitter array 320 has an effective incident area EA (an incident surface of light 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 equal to one half of the size WL of the condenser lens 311 in the x direction. The center (lens optical axis) 311c of the condenser lens 311 is arranged to be equal to the center of the effective incident area EA in the x direction. The effective incident area EA corresponds to an area where the polarization splitting film 331 is projected on the light incident surface of the polarization beam splitter 320. 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 addition, the corresponding polarization separation film 331 and reflection film 332 are not formed on the condenser lens 311 at the right end in FIG. 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 that the pitch of the polarization separation film 331 is set to a value different from the pitch of the lens optical axis 311c of the condenser lens 311 and the two polarization beam splitter arrays 320 ′ are set with the system optical axis L as the center. FIG. 9 is an explanatory diagram showing a case where a polarization separation film 331 and a reflection film 332 are arranged so as to face each other. In the drawings, the portion on the left side of the system optical axis is omitted.

The middle part of FIG. 12 shows a light amount distribution of light condensed by each of the lenses La to Ld of the condensing lens array 310 and irradiating the incident surface of the polarization beam splitter array 320 ′. In general, the light intensity Ia of the 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 the 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 is such that the closer to the optical axis, the closer to the optical axis the closer to the optical axis from a certain lens position (position of the third lens Lc in FIG. 12). , And the farther from the optical axis, the more the distribution is opposite 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 light amount distributions Pb and Pa are gradually closer to the system optical axis as the lenses Lb and La are closer to the optical axis. ing. 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 amount 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 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 set such that the interval between the polarization separating films 331 matches the interval between the peaks of the light amount distribution. It is preferable to adjust 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, and the distribution Pa of light emitted from the lens La near the light source optical axis is more deviated toward the light source optical axis than the center optical axis of the lens. It is preferable that the center of the effective incident area EA1 closest to the light source optical axis side of 320 ′ is almost aligned with the peak position of the light distribution Pa.

The configuration shown in FIG. 12 is different from the configuration shown in FIG. 12 in that the light intensity and the light amount distribution of the light emitted from each of the condensing lenses 311 of the condensing lens array 310 have the widths of the effective incident areas EA1 to EA4 and the invalid incident areas UA1 to UA4 (ie (Interval of the film 311). That is, the width Wp 'of the effective incident area EA (EA1 to EA4 in the drawing) and the invalid incident area UA (UA1 to UA4 in the drawing) of the polarizing beam splitter array 320' in the x direction is equal to each lens La of the condenser lens array 310. ＬLd is larger than １ ／ of the width WL in the x direction.

で は In the example of 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. Normally, the width of each invalid incident area UA is equal to the width Wp 'of the effective incident area EA. Therefore, the two effective incident areas EA2 and EA1 on the left are gradually shifted toward the system optical axis with respect to the centers of the lenses Lb and La. Become. The rightmost effective incident area EA4 is located 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, a predetermined number of lenses close to the optical axis, for example, two or three lenses, have a high light intensity, so that the light intensity 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 increased. 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 placed 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. It is determined.

In the examples of FIGS. 11 and 12 described above, 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 differ depending on the position. FIG. 13 is a plan view showing a condenser lens array 310 'having a plurality of types of small lenses having different sizes, and a sectional view taken along line BB of FIG. In FIG. 13A, a broken-line circle indicates a region where the light amount from the light source is relatively large.

In the condenser lens array 310 ′, a relatively large sized first small lens 312 is arranged in a matrix around the system optical axis L, and a relatively small sized second small lens 313 is collected. The lenses are arranged in a substantially matrix shape near the end of the 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 polarization beam splitter array (that is, the pitch of the polarization separation film). Are at least part of 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 (FIG. 10) so as to match the pitches of the corresponding small lenses 312 and 313. 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 separation film) is shifted from the corresponding small lens 312, 313. At least a part of 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 adjusted to match the pitch of the light quantity distribution of the emitted light flux.

B. Second embodiment:
14 to 19 are explanatory views showing a method for manufacturing a polarization beam splitter array according to the second embodiment. In the second embodiment, as shown in FIG. 14, an assembling 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 322 (film) shown in FIG. ) 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 the 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 translucent member 321 is overlaid thereon. In this manner, 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 brought into contact with the vertical wall 404. At this time, the dummy glass 324 and the first light-transmitting member 321 are shifted by a predetermined shift amount ΔH on the side surface perpendicular to the contacting side surface. In FIG. 15, ultraviolet light (indicated as “UV” in the figure) is irradiated from above the first translucent member 321 to cure the adhesive. The plate material thus bonded is referred to as a “first laminate”. Note that the ultraviolet light is preferably emitted 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.

(4) An adhesive is applied to the upper surface of the first laminate, and the second light-transmissive member 322 is laminated (FIG. 16). At this time, air bubbles contained in the adhesive layer are expelled while the first and second translucent members 321 and 322 stacked via the adhesive layer are rubbed, and the thickness of the adhesive layer is reduced. Make it even. 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, similarly, each time one light-transmitting member is laminated via the adhesive layer, the laminated body shown in FIG. 18 is cured by irradiating ultraviolet rays to cure the adhesive layer. can get. FIG. 19 shows a state in which the obtained laminate is cut. The stacked body is placed on the cutting table 410 with the side that has been in contact with the vertical wall 404 in FIG. 18 facing down. And it cut | disconnects along the parallel cutting line 328a, 328b. Thereafter, by polishing the cut surface flat, an element similar to that of the polarization beam splitter array of the first embodiment shown in FIG. 4 can be obtained. However, the polarizing beam splitter array produced in the second embodiment has a dummy glass 324 provided at an end.

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 relationship can be determined accurately. 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.

It should be noted that a laminate (“unit laminate”) obtained by bonding one sheet of the first light-transmitting member 321 and one sheet of the second light-transmitting member 322 in the same process as in the second embodiment. A plurality of unit laminates may be formed in advance and these unit laminates may be sequentially laminated. That is, one unit laminate may be laminated via the adhesive layer, bubbles in the adhesive layer are expelled, and then the adhesive layer is 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 translucent members 321 and 322 can be controlled when each surface is polished. 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 member surface.

C. Configuration of polarized illumination device and image display device:
FIG. 6 is a schematic configuration diagram of a main part of the polarized light illuminating device 1 having the polarized beam splitter array according to the above-described embodiment, as viewed in plan. The polarized light illumination device 1 includes a light source unit 10 and a polarized light generator 20. The light source unit 10 emits a light beam having a random polarization direction including an s-polarized component and a p-polarized component. The luminous flux emitted from the light source unit 10 is converted by the polarization generator 20 into one type of linearly polarized light having substantially uniform polarization directions, and illuminates the illumination area 90.

The light source unit 10 includes a light source lamp 101 and a parabolic reflector 102. The light emitted from the light source lamp 101 is reflected in one direction by the parabolic reflector 102, and enters the polarization generator 20 as a substantially parallel light flux. 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 certain distance D with respect to the system optical axis L. Here, the system optical axis L is the optical axis of the polarizing beam splitter array 320. The reason for shifting the light source optical axis R will be described later.

The polarization generator 20 includes a first optical element 200 and a second optical element 300. FIG. 7 is a perspective view showing the appearance of the first optical element 200. FIG. As shown in FIG. 7, 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. The outer shape of each light beam splitting lens 201 as viewed from the Z 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 to be long 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 condenser lens array 310, a polarizing beam splitter array 320, a selective phase plate 380, and an emission-side lens 390. As described with reference to FIG. 5, the selective phase difference plate 380 includes 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 321. Is a colorless and transparent plate-like body. 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 into a substantially rectangular parallelepiped shape.

The condensing lens array 310 has substantially the same configuration as the first optical element 200 shown in FIG. That is, the condensing lens array 310 is configured by arranging a plurality of condensing lenses 311 in the same number as the light beam splitting lenses 201 constituting the first optical element 200 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 converges on a plane perpendicular to the system optical axis L (XY plane in FIG. 1) by the light condensing action of the light beam splitting lens 201 and the condensing lens 311. At the position where the intermediate light beam 202 converges, the same number of light source images as the number of light beam splitting lenses 201 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 of the polarization separation film 331 in the X direction (FIG. 6). 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. 6, the center of the polarization separation film 331 for separating the intermediate light flux 202 is also shifted from the system optical axis L by Wp / 2. Accordingly, by shifting the light source optical axis R from the system optical axis L by Wp / 2, the light source image of the light source lamp 101 can be formed substantially at the center of the polarization separation film 331.

(5) The light beam incident on the polarization beam splitter array 320 is all converted to s-polarized light as shown in FIG. 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.

In the case where the parallelism of the light beam incident on the first optical element 200 is extremely good, the condensing lens array 310 can be omitted from the second optical element 300.

As described above, the polarization illuminating device 1 shown in FIG. 6 functions as a polarization generation unit that converts 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). The illumination area 90 is evenly illuminated with such a large number of polarized light beams. 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 including the polarized light illumination device 1 shown in FIG. This projection display device 800 includes a polarized light illumination device 1, dichroic mirrors 801 and 804, reflection mirrors 802, 807 and 809, relay lenses 806, 808 and 810, and three liquid crystal panels (liquid crystal light valves) 803. , 805, 811; a cross dichroic prism 813; and a projection lens 814.

The dichroic mirrors 801 and 804 have a function as a color light separating unit that separates a white light beam into three color lights of red, blue and green. The three liquid crystal panels 803, 805, and 811 have a function as light modulating units that form images by modulating the three color lights in accordance with given image information (image signals). 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 the synthesized color image on the screen 815.

The blue light green light reflecting dichroic mirror 801 transmits the red light component of the white light flux emitted from the polarized light illumination 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. On the other hand, of the blue light and the green light reflected by the first 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 also passes through the second dichroic mirror 804.

で は In this embodiment, the optical path length of blue light is the longest of the three color lights. Therefore, for the blue light, after the dichroic mirror 804, there is provided a light guiding means 850 composed of a relay lens system including an input lens 806, a relay lens 808, and an output lens 810. That is, after transmitting the blue light through the green light reflecting dichroic mirror 804, first, the blue light is guided to the relay lens 808 via the incident lens 806 and the reflecting mirror 807. Further, the light is reflected by the reflection mirror 809 and guided to the emission lens 810, and reaches the blue light liquid crystal panel 811. Note that the three liquid crystal panels 803, 805, and 811 correspond to the illumination area 90 in FIG.

(3) The three liquid crystal panels 803, 805, and 811 modulate respective color lights according to an image signal (image information) provided from an external control circuit (not shown), and generate color lights including image information of respective color components. The modulated three color lights enter the cross dichroic prism 813. 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 combined light is projected on a screen 815 by a projection lens 814, which is a projection optical system, and an image is enlarged and displayed.

In the projection display device 800, liquid crystal panels 803, 805, and 811 of a type that modulate a light beam (s-polarized light or p-polarized light) in a specific polarization direction are used as light modulation means. Usually, 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, there arises a problem that the light use efficiency is low and the polarizing plate generates heat. However, in the projection display device 800 shown in FIG. 8, since the luminous flux of a specific polarization direction that passes through the liquid crystal panels 803, 805, and 811 is generated by the polarization illuminating device 1, the light of 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 polarizing beam splitter array 320 according to the embodiment, there is also an advantage that the light use efficiency of the entire projection display device 800 is enhanced.

The reflection film 332 of the polarization beam splitter array 320 is formed of a dielectric multilayer film having a property of selectively reflecting only a specific polarization component (for example, s-polarized light) to be modulated by the liquid crystal panels 803, 805, and 811. Is preferred. By doing so, the problems of light absorption and heat generation in the liquid crystal panels 803, 805, 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 related art. Therefore, the image projected on the screen 815 can be made brighter.

The present invention is not limited to the above-described examples and embodiments, and 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 display device shown in FIG. 8, but 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 apparatus of FIG. 8, only one liquid crystal panel is required, and the color light separating means for separating the light beam into three colors and the color light combining means for combining the light beams of three colors can be omitted.

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

FIG. 9B illustrates an optical path of light incident on the incident surface 327 of the second translucent member 322 when the light-shielding plate 340 is not provided. The light that has entered the incident surface 327 is reflected by the reflection film 332a, and then 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 passes through the first optical adhesive layer 325a twice before reaching the upper reflective film 332b, and then passes through the next optical adhesive layer 325a. It passes once through the optical adhesive layer 325b. On the other hand, the p-polarized light component passes through the two optical adhesive layers 325a and 325b twice before reaching the λ / 2 retardation plate 381. As described above, when the light shielding plate 340 is not provided, light incident on the incident surface 327 of the second translucent member 322 passes through the optical adhesive layer 325 many times. Thus, as shown in FIG. 9A, by providing a light shielding plate 340, such light can be shielded.

Instead of providing the light-shielding plate 340 separately from the polarization beam splitter array 320, the light-shielding portion 341 is formed on the incident surface 327 of the second light-transmissive member 322 by an aluminum reflective film or the like. Is also good.

The figure which shows the schematic structure of a polarization conversion element. FIG. 4 is a process cross-sectional view showing main processes for manufacturing the polarizing beam splitter array according to the embodiment of the present invention. FIG. 4 is a process cross-sectional view showing main processes for manufacturing the polarizing beam splitter array according to the embodiment of the present invention. FIG. 2 is a perspective view showing a polarizing beam splitter array 320 according to the embodiment. FIG. 4 is a cross-sectional plan view showing a polarization conversion element of an example and a comparative example in comparison. FIG. 1 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. 2 is a perspective view illustrating an appearance of a first optical element 200. FIG. 1 is a schematic configuration diagram illustrating a main part of a projection display device 800 including a polarized light illumination device 1. FIG. 4 is an explanatory diagram illustrating a configuration of an optical element having a light blocking plate 340. FIG. 3 is an enlarged cross-sectional view illustrating a polarization beam splitter array 320 according to the embodiment in detail. FIG. 4 is a cross-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. 9 is an explanatory diagram showing a case where the pitch of the polarization separation film 331 is set to a value different from the pitch of the lens optical axis 311c of the condenser lens 311. FIG. 4 is a plan view showing a condenser lens array 310 ′ having a plurality of types of small lenses having different sizes, and a BB cross-sectional view thereof. FIG. 11 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment. FIG. 11 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment. FIG. 11 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment. FIG. 11 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment. FIG. 11 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment. FIG. 11 is an explanatory diagram illustrating a method for manufacturing a polarization beam splitter array according to the second embodiment.

Explanation of reference numerals

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 ... light collecting lens array 311 ... light collecting 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 Light transmissive part 380 Selected phase plate 381 λ / 2 phase plate 3 0: Outgoing 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

Claims (20)

An optical element,
First and second substantially parallel films having a light incident surface and a light exit surface substantially parallel to the light incident surface, and formed at a predetermined angle with the light incident surface and the light exit surface. A plurality of first light-transmissive members each including a forming surface, a polarization separating film formed on the first film forming surface, and a reflecting film formed on the second film forming surface; ,
A light incident surface and a light exit surface that are alternately bonded to the plurality of first light transmissive members and are respectively formed on the same plane as the light incident surface and the light exit surface of the plurality of first light transmissive members. A plurality of second translucent members each having
An optical element comprising: The optical element according to claim 1,
The optical element, wherein the reflection film is formed of a dielectric multilayer film. The optical element according to claim 1 or 2, further comprising:
An optical element comprising: a polarization direction changing unit provided corresponding to the light exit surface of the first light transmissive member or the light exit surface of the second light transmissive member. The optical element according to claim 1 or 2, further comprising:
An optical element having a light blocking means provided corresponding to the light incident surface of the second light transmitting member. An optical element according to any one of claims 1 to 4, wherein
An adhesive layer is provided on an interface between the first and second translucent members, respectively.
At least a part of the thickness of the first and second translucent members and the thickness of the adhesive layer is set so that the distance between the polarization splitting film and the reflection film is substantially equal through the optical element. Optical element. The optical element according to claim 5, wherein
An optical element, wherein the thickness of the second light transmitting member is set smaller than the thickness of the first light transmitting member. The optical element according to claim 6,
An optical element wherein the thickness of the second light transmissive member is in a range from about 80% to about 90% of the thickness of the first light transmissive member. The optical element according to claim 5, wherein:
An optical element, wherein the thickness of the first light transmitting member is substantially equal to a value obtained by adding twice the thickness of the adhesive layer to the thickness of the second light transmitting member. An optical element according to any one of claims 1 to 4, wherein
The optical element is an optical element used with a plurality of small lenses arranged on the 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. The optical element according to claim 9,
An adhesive layer is provided on an interface between the first and second translucent members, respectively.
The thickness of the first and second light-transmissive members and the thickness of the adhesive layer such that the interval between the plurality of polarization separation films substantially corresponds to the pitch of the lens optical axes of the plurality of small lenses. An optical element, at least a part of which is set. The optical element according to claim 10,
The plurality of small lenses have a plurality of different lens optical axis pitches,
The distance between the plurality of polarized light separating films is substantially equal to the plurality of different lens optical axis pitches, and the distance between the thickness of the first and second translucent members and the thickness of the adhesive layer is selected. An optical element, at least a part of which is set. An optical element according to any one of claims 1 to 4, wherein
The optical element is an optical element used with a plurality of small lenses arranged on the 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. The optical element according to claim 12, wherein
An adhesive layer is provided on an interface between the first and second translucent members, respectively.
The thickness of the first and second light-transmitting members and the thickness of the adhesive layer such that a mutual interval between the plurality of polarization separation films substantially corresponds to a pitch of a plurality of light beams emitted from the plurality of small lenses. An optical element, at least a part of which is set. A method for manufacturing an optical element, comprising:
(A) forming a polarization splitting film on the first surface of a first light-transmitting plate having substantially parallel first and second surfaces;
(B) forming a reflective film on the second surface of the first translucent plate;
(C) The plurality of first light-transmitting plate members on which the polarization separation film and the reflection film are formed, and the plurality of second light-transmitting plate members having two substantially parallel surfaces are alternately bonded to each other. Process and
(D) cutting the translucent plate members alternately bonded to each other at a predetermined angle with respect to the first and second surfaces to form an optical element block having a light incidence surface and a light emission surface which are substantially parallel to each other; Generating,
A method for producing an optical element having: The method for manufacturing an optical element according to claim 14, further comprising:
(E) polishing the light incident surface and the light exit surface of the optical element block;
The manufacturing method of the optical element provided with. It is a manufacturing method of the optical element of Claim 14 or Claim 15, Comprising:
The step (c) is 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;
The manufacturing method of the optical element provided with. It is a manufacturing method of the optical element of Claim 14 or Claim 15, Comprising:
The step (c) comprises:
(1) forming a laminate by laminating one sheet of the first translucent member and one sheet of the second translucent member via a photocurable adhesive layer; ,
(2) curing the photocurable adhesive layer by irradiating the laminate with light;
(3) The first light-transmissive member and the second light-transmissive member are alternately stacked on the laminate via the photocurable adhesive layer. A step of curing the photocurable adhesive layer by irradiating the laminate with light each time it is stacked,
The manufacturing method of the optical element provided with. It is a manufacturing method of the optical element of Claim 14 or Claim 15, Comprising:
The step (c) comprises:
(1) forming a laminate by laminating one sheet of the first translucent member and one sheet of the second translucent member via a photocurable adhesive layer; ,
(2) curing the photocurable adhesive layer by irradiating the laminate with light;
(3) The plurality of laminates created in the steps (1) and (2) are alternately stacked via the photocurable adhesive layer. In this case, each time one laminate is stacked Curing the photocurable adhesive layer by irradiating light,
The manufacturing method of the optical element provided with. A method for manufacturing an optical element according to any one of claims 16 to 18, wherein
The light irradiation is performed from a direction that is not parallel to the surface of the translucent member,
A method for manufacturing an optical element. An optical element according to any one of claims 1 to 13,
Polarization conversion means for converting the light emitted from the optical element to one type of polarized light,
Modulation means for modulating the light emitted from the polarization conversion means based on a given image signal,
A projection optical system that projects the light beam modulated by the modulation unit,
Projection display device comprising:

Images