JP2022150711A - Polarization conversion element, light source device, and projector - Google Patents

Abstract

To provide a polarization conversion element that can prevent a deterioration in angle dependence of incident light.SOLUTION: A polarization conversion element of the present invention comprises: a first light transmissive member that has an incident surface on which light is incident, a pair of first inclined surfaces, and an emission surface from which light is emitted; a second light transmissive member that has a pair of second inclined surfaces and an emission surface from which light is emitted; a polarization separation film that is arranged between one of the first inclined surfaces and one of the second inclined surfaces and separates the light incident on the first light transmissive member into first polarized light and second polarized light; a reflective film that is arranged on the other of the first inclined surfaces and reflects the first polarized light reflected by the polarization separation film to the emission surface of the first light transmissive member; and a half-wavelength phase difference plate that is arranged between the polarization separation film and one of the second inclined surfaces, converts the second polarized light having transmitted through the polarization separation film into the first polarized light, and guides the light to the second light transmissive member. The half-wavelength phase difference plate has an inorganic material whose growth direction is a direction orthogonal to a direction of travel of the second polarized light transmitting through the polarization separation film.SELECTED DRAWING: Figure 3

Description

The present invention relates to a polarization conversion element, a light source device and a projector.

2. Description of the Related Art Projectors and other display devices use a light-emitting element, a polarization conversion element for converting light generated by a lamp or a laser light source into one type of linearly polarized light and emitting the light. For example, in Patent Document 1, a polarization separation film and a reflective film and a position are arranged alternately so as to be inclined with respect to a light incident surface and a light exit surface parallel to each other in a light transmissive substrate. A polarization conversion element with a retardation plate is disclosed. The retardation plate is made of, for example, an obliquely vapor-deposited inorganic material in order to have heat resistance and light resistance. Patent Document 2 discloses a birefringent layer (position layer) formed by alternately depositing an inorganic substance every predetermined thickness from two directions symmetrical with respect to the normal to the light incident surface and the light exit surface of the substrate. a retardation plate) and a polarization conversion element comprising the birefringent layer.

JP 2009-192868 A JP 2014-219672 A

In the polarization conversion element disclosed in Patent Literature 1, by overlapping the polarization separation film and the retardation plate, it is possible to suppress the generation of shadows caused by the edge portions of the retardation plate. In the polarization conversion element disclosed in Patent Document 2, since a plurality of layers in which the directions of inclination of the inorganic substances are different from each other are laminated, the direction in which the incident light is incident deviates from the direction perpendicular to the light incident surface. It is possible to compensate for the time and reduce the incident angle dependence of the efficiency of incident light. When the structure of the birefringence layer of Patent Document 2 is applied to the polarization conversion element of Patent Document 1, the symmetry of the columnar body made of inorganic material with respect to the optical axis is lost, and as a result, the birefringence and polarization conversion characteristics of the retardation plate deteriorate. There is a risk that the angle dependency will deteriorate.

In order to solve the above problems, a polarization conversion element of one aspect of the present invention provides a first translucent member having an incident surface on which light enters, a pair of first inclined surfaces, and an exit surface from which light exits. and a second translucent member having a pair of second inclined surfaces and an exit surface through which light exits, one of the pair of first inclined surfaces and one of the pair of second inclined surfaces It is arranged between one second inclined surface and reflects the first polarized light that is one polarized component of the light incident on the first translucent member, and reflects the second polarized light that is the other polarized component of the light incident on the first translucent member. A polarization separation film that separates the light incident on the first translucent member by transmission, and the first polarized light that is arranged on the other first inclined surface of the pair of first inclined surfaces and reflected by the polarization separation film. to the exit surface of the first light-transmitting member, and the second polarized light transmitted through the polarization separation film is arranged between the polarization separation film and one second inclined surface, and the second polarized light transmitted through the polarization separation film is converted into the first polarized light. a half-wave retardation plate for converting and guiding the light to the second translucent member. The half-wave retardation plate is an oblique deposition film having an inorganic material whose growth direction is orthogonal to the traveling direction of the second polarized light that passes through the polarization splitting film.

1 is a schematic configuration diagram of a projector according to a first embodiment; FIG. 2 is a schematic configuration diagram enlarging a part of a light source device provided in the projector of FIG. 1; FIG. FIG. 3 is a schematic configuration diagram in which a region R10 shown in FIG. 2 is enlarged; FIG. 5 is a schematic configuration diagram in which a part of a polarization conversion element of a modified example of the first embodiment is enlarged; FIG. 10 is a schematic configuration diagram enlarging a part of the polarization conversion element of the second embodiment; FIG. 10 is a schematic diagram showing the relative relationship of the optical axis azimuth angles in the retardation plate of the polarization conversion element of the second embodiment; 9 is a graph showing an example of the wavelength dependence of the polarization conversion efficiency of the retardation plate of the polarization conversion element of the second embodiment; FIG. 11 is a schematic configuration diagram in which a part of the polarization conversion element of the third embodiment is enlarged;

[First embodiment]
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG.
FIG. 1 is a schematic diagram showing the configuration of the projector 1 of the first embodiment. In each of the drawings below, the scale of the dimensions may be changed depending on the component in order to make each component easier to see.

The projector of this embodiment is an example of a projector having three transmissive liquid crystal light valves as light modulation devices. For example, a reflective liquid crystal light valve may be used as the light modulation device. As the light modulating device, a light modulating device other than liquid crystal may be used, such as a device using a micromirror or a device including a DMD (Digital Micromirror Device).

(projector)
First, the configuration of the projector 1 will be described.
As shown in FIG. 1, the projector 1 includes a light source device 11, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G and a light modulation device 4B, a light combining optical system 5, and a projection optical system 6. , provided.

(light source device)
The light source device 11 includes a light source 15, an integrator optical system 31, a polarization conversion element 100, and a superimposing lens 33A. The light source 15 emits white light WL, which is illumination light for the projector 1 . The light source 15 is, for example, a white lamp that emits white light, or a light emitting module that emits white light by mixing blue light emitted from a laser light source and yellow light emitted from a phosphor using the blue light as excitation light. However, it is not particularly limited as long as it can emit white light WL. The white light WL emitted from the light source 15 is unpolarized, that is, in a state in which a plurality of linearly polarized lights are superimposed and the polarization state cannot be observed as a whole. Note that the detailed configuration of the light source 15 is omitted in FIG.

White light WL emitted from the light source 15 is emitted toward the integrator optical system 31 . The integrator optical system 31 includes, for example, a lens array 31A and a lens array 31B. In each of the lens arrays 31A, 31B, a plurality of microlenses 32A, 32B are arranged along a direction perpendicular to the optical axis AX. The integrator optical system 31 and the superimposing lens 33A constitute a superimposing optical system 33. As shown in FIG.

The white light WL that has passed through the integrator optical system 31 enters the polarization conversion element 100 . The polarization conversion element 100 converts the non-polarized white light WL into linearly polarized light. The white light WL transmitted through the polarization conversion element 100 enters the superimposing lens 33A. The superimposing lens 33A cooperates with the integrator optical system 31 to homogenize the illuminance distribution of the white light WL in the illuminated area.

The color separation optical system 3 separates the white light WL emitted from the superimposing lens 33A of the light source device 11 along the optical axis AX into red light LR, green light LG and blue light LB. The light modulating device 4R, the light modulating device 4G, and the light modulating device 4B respectively modulate the red light LR, the green light LG, and the blue light LB according to the image information to form image light of each color. The light synthesizing optical system 5 synthesizes the image light of each color emitted from the light modulating device 4R, the light modulating device 4G, and the light modulating device 4B. The projection optical system 6 projects the image light synthesized by the light synthesis optical system 5 toward the screen SCR.

The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflecting mirror 8a, a second reflecting mirror 8b, and a third reflecting mirror 8c. The first dichroic mirror 7a separates the white light WL emitted from the light source device 11 into red light LR and mixed light of green light LG and blue light LB. Therefore, the first dichroic mirror 7a transmits the red light LR and reflects the green light LG and the blue light LB. The second dichroic mirror 7b separates the mixed light of green light LG and blue light LB into green light LG and blue light LB. Therefore, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB.

The first reflecting mirror 8a is arranged in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulation device 4R. The second reflecting mirror 8b and the third reflecting mirror 8c are arranged in the optical path of the blue light LB, reflect the blue light LB transmitted through the second dichroic mirror 7b, and guide the blue light LB to the light modulator 4B.

The light modulation device 4R modulates the red light LR according to image information while passing the red light LR to form red image light. Similarly, the light modulator 4G modulates the green light LG in accordance with the image information while allowing the green light LG to pass therethrough to form green image light. The light modulation device 4B modulates the blue light LB according to the image information while passing the blue light LB to form blue image light. Each of the light modulating device 4R, the light modulating device 4G, and the light modulating device 4B is configured by, for example, a liquid crystal panel.

A polarizing plate (not shown) is arranged on the light incident side and the light exit side of each of the light modulating device 4R, the light modulating device 4G, and the light modulating device 4B. A field lens 10R that converts the red light LR incident on the light modulation device 4R into parallel light is provided on the incident side of the light modulation device 4R for the red light LR. A field lens 10G for converting the green light LG incident on the light modulation device 4G into parallel light is provided on the side of the light modulation device 4G on which the green light LG is incident. A field lens 10B that converts the blue light LB entering the light modulation device 4B into parallel light is provided on the side of the light modulation device 4B from which the blue light LB is incident.

The light synthesizing optical system 5 is composed of, for example, a cross dichroic prism. The light synthesizing optical system 5 synthesizes the image light of each color emitted from each of the light modulator 4R, the light modulator 4G, and the light modulator 4B, and emits the synthesized image light toward the projection optical system 6.

The projection optical system 6 is composed of a plurality of projection lenses. The projection optical system 6 enlarges and projects the image light synthesized by the light synthesis optical system 5 toward the screen SCR. An enlarged color image is displayed on the screen SCR.

(polarization conversion element)
Next, the configuration of the polarization conversion element 100 will be described.
FIG. 2 is a schematic configuration diagram enlarging a part of the lens array 31B and the polarization conversion element 101 of the first embodiment in the light source device 11 described above. FIG. 3 is a schematic configuration diagram in which the region R10 shown in FIG. 2 is enlarged.

The white light WL is condensed and incident on the polarization conversion element 101 from each of the plurality of microlenses 32B provided in the lens array 31B. Hereinafter, the traveling direction of the white light WL entering the polarization conversion element 101, that is, the direction parallel to the optical axis of the white light WL entering the polarization conversion element 101 is defined as the Z direction. Two directions perpendicular to the Z direction and orthogonal to each other are defined as the X direction and the Y direction, and a plane including the X direction and the Y direction is referred to as the XY plane.

The polarization conversion element 101 has surfaces 101a and 101b, a pair of side surfaces 101c and 101e, and a pair of side surfaces 101d and 101f, and has a plate shape. Note that FIG. 3 shows the side surface 101e of the pair of side surfaces 101c and 101e. The surfaces 101a and 101b are arranged parallel to the XY plane and have a substantially square shape when viewed from the Z direction. The surface 101a constitutes the incident surface of the white light WL. The surface 101b constitutes the exit surface of the white light WL. The side surfaces 101d and 101f are arranged parallel to an XZ plane that includes the X direction and the Z direction and is perpendicular to the Y direction, and has a long side along the X direction and a short side along the Z direction when viewed from the Y direction. It has a rectangular shape. The side surface 101e is arranged parallel to a YZ plane that includes the Y direction and the Z direction and is perpendicular to the X direction, and has a rectangular shape having a long side along the Y direction and a short side along the Z direction when viewed from the X direction. is making

The polarization conversion element 101 includes a plurality of first light-transmitting members 110, a plurality of second light-transmitting members 120, a plurality of light shielding films 130, a plurality of polarization separating films 140, a plurality of reflecting films 150, A plurality of retardation plates 160 and a plurality of antireflection films 181 and 182 are provided.

The first translucent member 110 has surfaces 110a and 110b, a pair of side surfaces 110c and 110e, and a pair of side surfaces 110d and 110f, and is formed in a columnar shape extending in the Y direction. The surfaces 110a and 110b are arranged parallel to the XY plane and have a rectangular shape with long sides along the Y direction and short sides along the X direction when viewed from the Z direction. The surface 110a is the incident surface 111 on which the white light WL is incident. The surface 110b is the exit surface 112 from which the white light WL exits. The side surfaces 110c and 110e are arranged parallel to each other in the X direction, and have a rectangular shape having a long side along the Y direction and a short side along the Z direction when viewed from the X direction. However, the side surfaces 110c and 110e recede in the X direction as they move forward in the Z direction, and are inclined with respect to the X and Z directions when viewed from the Y direction. That is, the side surfaces 110c and 110e are a pair of inclined surfaces (first inclined surfaces) 114A and 114B. The side surfaces 110d and 110f face each other in the Y direction and are arranged parallel to the XZ plane and parallel to each other. It has a parallelogram shape with two sides parallel to each other and receding in direction. Note that the pair of inclined surfaces (first inclined surfaces) 114A and 114B are also inclined surfaces that are inclined with respect to the incident surface 111 .

The second translucent member 120 has surfaces 120a and 120b, a pair of side surfaces 120c and 120e, and a pair of side surfaces 120d and 120f, and is formed in a columnar shape extending in the Y direction. The surfaces 120a and 120b are arranged parallel to the XY plane and have a rectangular shape with long sides along the Y direction and short sides along the X direction when viewed from the Z direction. The surface 120b is the exit surface 122 from which the white light WL exits. The side surfaces 120c and 120e are arranged parallel to each other in the X direction and have a rectangular shape with long sides along the Y direction and short sides along the Z direction when viewed from the X direction. Like the side surfaces 110c and 110e, the side surfaces 120c and 120e recede in the X direction as they move forward in the Z direction, and are inclined with respect to the X and Z directions when viewed from the Y direction. That is, the side surfaces 120c and 120e are a pair of inclined surfaces (second inclined surfaces) 124A and 124B. The side surfaces 120d and 120f face each other in the Y direction and are arranged parallel to the XZ plane and parallel to each other. It has a parallelogram shape with two sides that are receding and parallel to each other. Note that the pair of inclined surfaces (second inclined surfaces) 124A and 124B are also inclined surfaces that are inclined with respect to the incident surface 111 .

The first translucent members 110 and the second translucent members 120 are alternately arranged in the X direction such that the side surfaces 110c and 120e face each other and the side surfaces 120c and 110e face each other.

As described above, the entire polarization conversion element 101 is formed in a plate shape, and the side surfaces 101d and 101f are rectangular when viewed from the Y direction. Therefore, in the X direction, the side surfaces 110d and 110f of the first translucent member 110 and the side surfaces 120d and 120f of the second translucent member 120 arranged at both ends are parallel to the X direction when viewed from the Y direction. a first side connected to one end of the first side and perpendicular to the first side and parallel to the Z direction; the other end of the first side and the second side connected to the first side It forms a right-angled triangular shape which connects the opposite end to the opposite end and has a third side which recedes in the X direction as it progresses in the Z direction and which is parallel to each other.

The first translucent member 110 and the second translucent member 120 are made of, for example, various types of optical glass, white plate glass, borosilicate glass, soda plate glass, etc., and have translucency with respect to white light WL. It is not particularly limited as long as it is a base material.

The light shielding film 130 is a film for shielding the white light WL, and is arranged so as to cover the surface 120a of the second translucent member 120 . As shown in FIG. 2, the white light WL condensed by the microlens 32B is generally incident on the surface 110a, ie, the incident surface 111, among the surfaces 110a and 120a alternately arranged in the X direction. Even if a small amount of the white light WL condensed by the microlens 32B irradiates a region overlapping the surface 120a in the X direction, it is blocked by the light shielding film 130 and does not enter the surface 120a. That is, the surface 120a is not an incident surface on which the white light WL is incident. The light shielding film 130 is composed of, for example, a reflective film such as a metal film or a dielectric film.

The plane of incidence of the white light WL in the polarization conversion element 101 is composed of a plurality of planes of incidence 111 arranged in the X direction with the light shielding films 130 interposed therebetween. On the other hand, the emission surface of the white light WL in the polarization conversion element 101 is composed of a plurality of emission surfaces 112 and a plurality of emission surfaces 122 alternately arranged in the X direction.

The polarization splitting film 140 is formed between the inclined surface (one first inclined surface) 114A of the pair of inclined surfaces 114A and 114B of the first translucent member 110 and the second translucent surface above the first translucent member 110. It is arranged between the inclined surface (one second inclined surface) 124B of the pair of inclined surfaces 124A and 124B of the optical member 120 . The polarization splitting film 140 reflects the S-polarized light (the first polarized light that is one of the polarized components) WL _S of the non-polarized white light (light) WL incident from the incident surface 111 of the first translucent member 110 . do. Also, the polarization splitting film 140 transmits _P -polarized light (the second polarized light that is the other polarization component) WLP of the non-polarized white light WL incident from the incident surface 111 . That is, the polarization separation film 140 reflects the S-polarized light WL _S and transmits the P-polarized light WL _P , thereby separating the white light WL incident from the incident surface 111 into two lights having different polarization components.

The polarization splitting film 140 is, for example, a dielectric multilayer in which low refractive index layers made of magnesium fluoride (MgF ₂ ) and high refractive index layers made of lanthanum aluminate are alternately laminated with a predetermined number of layers and an optical thickness. composed of a membrane.

The reflective film 150 is arranged on the inclined surface (the other first inclined surface) 114B of the pair of inclined surfaces 114A and 114B of the first translucent member 110 . S-polarized light WL _S separated by the polarization separating film 140 is incident on the reflecting film 150 . The reflective film 150 reflects the _S -polarized light WLS reflected by the polarization separation film 140 to the exit surface 112 of the first translucent member 110 . The reflective film 150 is composed of, for example, a white light WL dielectric multilayer film or a metal film such as aluminum (Al) or silver (Ag). A dielectric multilayer film is preferably used as the reflective film 150 in order to further increase the reflectance.

As shown in FIGS. 2 and 3, the retardation plate 160 is arranged between the polarization separation film 140 and the inclined surface 124B of the pair of inclined surfaces 124A and 124B of the second translucent member 120. As shown in FIGS. . The retardation plate 160 is a half-wave retardation plate that imparts a half wavelength, that is, a phase amount of π to the _P -polarized light WLP transmitted through the polarization splitting film 140 and converts it into _S -polarized light (first polarized light) WLS. . The retardation plate 160 guides the converted S-polarized light WL _S to the second translucent member 120 .

As shown in FIG. 3, the half-wave retardation plate 160 is a so-called columnar structure film, which is an oblique deposition film having a plurality of inorganic columns (inorganic materials) 162 . The plurality of inorganic columnar bodies 162 are arranged side by side along the Z direction. Each inorganic columnar body 162 is formed by oblique vapor deposition on the side surface 160 e of the retardation plate 160 . A side surface 160e of the retardation plate 160 recedes in the X direction as it progresses in the Z direction, and is inclined with respect to the X and Z directions.

The growth direction D162 when the inorganic columnar bodies 162 are obliquely deposited, that is, the columnar core direction of the inorganic columnar bodies 162 is substantially parallel to the X direction and inclined with respect to the side surface 160e of the retardation plate 160 . As indicated by a two-dot dashed line in FIG. 3, unpolarized white light WL incident from the incident surface 111 of the first translucent member 110, P-polarized light WL _P transmitted through the polarization separation film 140, and a half-wave phase difference The traveling direction _DWL of each of the _S -polarized light WLS converted by the plate 160 and guided to the second translucent member 120 is parallel to the Z direction. The growth direction D ₁₆₂ of each inorganic columnar body 162 is parallel to the X direction and perpendicular to the traveling direction D _WL of the _P -polarized light WLP. The plurality of inorganic columnar bodies 162 are only in one direction of growth direction D ₁₆₂ .

It should be noted that the fact that the growth direction D ₁₆₂ of the inorganic columnar body 162 is orthogonal to the traveling direction D _WL of the P-polarized WL _P means that the P-polarized WL _P incident on the retardation plate 160 and the S Does not affect the symmetry about the optical axis of the polarization WL _S and the birefringence and polarization conversion properties in the retarder 160 from P-polarization WL _P to S-polarization WL _S , or P-polarization WL _P and S-polarization WL _S light This means that the symmetry about the axis and the birefringence and polarization conversion properties in the retarder 160 are minimally affected. Therefore, the angle α between the growth direction D ₁₆₂ of the inorganic columnar body 162 and the traveling direction D _WL of the P-polarized light WL _P is 90°±5°, preferably 90°±2°, most preferably 90°.

The inorganic columnar body 162 is made of crystal, for example. That is, the inorganic material of the half-wave retardation plate 160 is crystal, for example. Since the half-wave retardation plate 160 is composed of inorganic columnar bodies 162 such as crystal, organic films or silicon oxide (SiO ₂ ) and titanium oxide (TiO ₂ ) are alternately laminated in the conventional manner. Compared with a retardation film made of a dielectric multilayer film such as a laminated film, the heat resistance and light resistance are improved, and the lifetime of the polarization conversion element 101 can be extended.

The antireflection film 181 is arranged between the polarization separation film 140 and the retardation plate 160 . The anti-reflection film 181 prevents the _P -polarized WLP transmitted through the polarization splitting film 140 from being reflected by the retardation plate 160 and allows the _P -polarized WLP to enter the retardation plate 160 smoothly. The antireflection film 182 is arranged between the retardation plate 160 and the second translucent member 120 . The antireflection film 182 prevents the _S -polarized light WLS emitted from the retardation plate 160 from being reflected by the second translucent member 120 , allowing the _S -polarized light WLS to smoothly enter the retardation plate 160 .

The antireflection films 181 and 182 are formed of, for example, dielectric multilayer films. A material forming the dielectric multilayer film of the antireflection film 181 is selected according to the effective refractive index of the polarization separating film 140 and the effective refractive index of the retardation plate 160 . A material forming the dielectric multilayer film of the antireflection film 182 is selected according to the effective refractive index of the retardation plate 160 and the refractive index of the second translucent member 120 .

In the polarization conversion element 101 of the first embodiment, the plurality of inorganic columns 162 of the retardation plate 160 are formed on a substrate different from the substrate on which the polarization separation film 140 is formed. For example, as shown in FIG. 2, the second translucent member 120 is used as a substrate, the antireflection film 182 is directly formed on the side surface 120e of the second translucent member 120, and the antireflection film 182e is formed on the side surface 182e of the antireflection film 182. A retardation plate 160 consisting of a plurality of inorganic columns 162 extending along the growth direction D ₁₆₂ is directly formed. Furthermore, an antireflection film 181 is formed on the side surface 160 e of the retardation plate 160 . On the other hand, the reflective film 150 is directly formed on the side surface 120c of the second translucent member 120, and the first translucent member The first translucent member 110 is arranged so that the side surface 110e of 110 is in contact with it. A polarization separation film 140 is directly formed on the side surface 110c of the first translucent member 110, and an antireflection film 181, a half-wave retardation plate 160, an antireflection film 182, and an antireflection film 182 are formed from rear to front in the X direction. A basic laminate is formed of the second translucent member 120 , the reflective film 150 , the first translucent member 110 and the polarization separation film 140 . That is, in the polarization conversion element 101 of the first embodiment, the plurality of inorganic columnar bodies 162 of the retardation plate 160 are the second light-transmitting members different from the first light-transmitting member 110 on which the polarization separation film 140 is formed. It is obliquely vapor-deposited on the conductive member 120 .

The plurality of inorganic columnar bodies 162 are obtained by obliquely depositing the inorganic material of the inorganic columnar bodies 162 on the second translucent member 120 having the antireflection film 182 laminated on the side surface 120e, for example, as a base material. can be made by In this step, the side surface 182e of the antireflection film 182 on the base material is inclined at approximately 45° with respect to both the central direction in which the inorganic material is emitted from the inorganic material emitting device and the plane perpendicular to the central direction. It should be placed in a state where

In the polarization conversion element 101 of the first embodiment, the polarization separation film 140 and the antireflection film 181 are adhered with an adhesive 190 . For the adhesive 190, for example, an ultraviolet curing resin or the like is used. When the adhesive 190 penetrates into the inorganic columnar bodies 162 of the retardation plate 160, the birefringence of the retardation plate 160 is reduced, and a desired retardation cannot be obtained, resulting in a decrease in the polarization conversion efficiency of the retardation plate 160. do. Therefore, the antireflection film 181 plays a role of preventing the _P -polarized light WLP transmitted through the polarization separation film 140 from being reflected by the retardation plate 160 as described above. It plays a role of preventing intrusion into the inorganic columnar body 162 of .

In the polarization conversion element 101 of the first embodiment, the plurality of basic laminates described above are adhered to each other with an adhesive 190 and laminated in the X direction. In other words, the adhesive 190 is interposed between the polarization separation film 140 of the lower basic laminate and the antireflection film 181 of the upper basic laminate among the basic laminates adjacent to each other in the X direction.

In the polarization conversion element 101 of the first embodiment described above, the first translucent member 110 having the incident surface 111, the inclined surfaces 114A and 114B, and the exit surface 112, the inclined surfaces 124A and 124B, and the exit surface 122 are arranged. a second translucent member 120 having a second translucent member 120, a polarization separation film 140 disposed between an inclined surface 114A of the first translucent member 110 and an inclined surface 124B of the second translucent member 120, and a first translucent a reflective film 150 arranged on the inclined surface 114B of the optical member 110; The polarization separating film 140 reflects the _S -polarized light WLS of the white light WL incident on the first translucent member 110 and transmits the _P -polarized light WLP. The reflective film 150 reflects the S-polarized light WLS reflected by the polarization separation film 140 to the exit surface 112 of the first translucent member 110 . The retardation plate 160 converts the _P -polarized light WLP transmitted through the polarization separation film 140 into the _S -polarized light WLS, and guides the light to the second translucent member 120 . The retardation plate 160 is an oblique deposition film having inorganic columns 162 whose growth direction D ₁₆₂ is perpendicular to the traveling direction D _WL of the _P -polarized light WLP transmitted through the polarization splitting film 140 .

In the polarization conversion element 101 of the first embodiment, as shown in FIGS. 2 and 3, unpolarized white light WL is condensed and incident from each of the plurality of microlenses 32B included in the lens array 31B. The incident white light WL is separated into P-polarized light WL _P and S-polarized light WL _S by the polarization separation film 140 . The P-polarized light WL _P separated by the polarization separation film 140 passes through the polarization separation film 140 and is converted into the S-polarized light WL _S by the retardation plate 160 . The converted S-polarized light WL _S travels along the travel direction DWL, is guided to the second translucent member 120 , and emerges from the exit surface 122 . On the other hand, the S-polarized light WL _S separated by the polarization separating film 140 is specularly reflected by the reflecting film 150 in the first translucent member 110 and emitted from the exit surface 112 . That is, according to the polarization conversion element 101 of the first embodiment, the incident non-polarized white light WL can be converted into the S-polarized light WL _S , and the S-polarized light WL _S can be emitted from the surface 101b, which is the exit surface. In addition, according to the polarization conversion element 101 of the first embodiment, the retardation plate 160 includes a plurality of inorganic columns 162, so heat resistance and light resistance can be improved compared to the case of including a dielectric multilayer film. .

In the polarization conversion element 101 of the first embodiment, the growth direction D162 of the plurality of inorganic columnar bodies 162 of the retardation plate 160 is the traveling direction of the _P -polarized light WLP incident on the retardation plate 160 after passing through the polarization separation film 140. Orthogonal to the DWL. As a result, the symmetry with respect to the optical axis of the _P -polarized light WLP transmitted through the polarization separation film 140 is maintained to the maximum, and the incident angle dependence of the birefringence of the _P -polarized light WLP in the retardation plate 160 is reduced. can suppress variations in polarization conversion characteristics. As a result, the _P -polarized light WLP incident on the retardation plate 160 can be efficiently converted into the _S -polarized light WLS. Further, in the polarization conversion element 101 of the first embodiment, the influence of the shadow of the edge portion on the polarization conversion characteristics can be suppressed as compared with the conventional polarization conversion element formed of a dielectric multilayer film or the like. For these reasons, according to the polarization conversion element 101 of the first embodiment, the generation of shadows caused by the edge portion is suppressed, and the birefringence of the retardation plate 160 and deterioration of the angle dependence of the polarization conversion characteristics are suppressed. A decrease in light utilization efficiency can be prevented.

In the polarization conversion element 101 of the first embodiment, for example, like the polarization conversion element disclosed in the above-mentioned Patent Document 2, the traveling direction of the incident polarized light and the direction perpendicular to the traveling direction are inclined. A large birefringence, that is, a phase difference, occurs compared to a polarization conversion element having a zigzag-shaped or V-shaped columnar structure or a layered structure in which the orientation is alternately switched to the opposite side. Therefore, according to the polarization conversion element 101 of the first embodiment, compared to a conventional polarization conversion element having a zigzag-shaped or V-shaped columnar body or a layered structure in a side view, in order to develop a desired phase difference, The thickness of the half-wave retardation plate 160, that is, the size in the direction perpendicular to each of the side surface 110c of the first translucent member 110 and the side surface 120e of the second translucent member 120 can be reduced. As a result, the manufacturing cost of the polarization conversion element 101 can be suppressed and the quality of the polarization conversion element 101 can be improved.

As a modified example of the polarization conversion element 101 of the first embodiment, there is a polarization conversion element 102 shown in FIG. FIG. 4 is a schematic configuration diagram in which a region corresponding to the region R10 shown in FIG. 2 of the polarization conversion element 101 of the first embodiment is enlarged in the polarization conversion element 102 of the modified example of the first embodiment. As shown in FIG. 4, in the polarization conversion element 102, the plurality of inorganic columns 162 of the retardation plate 160 are obliquely vapor-deposited on the first translucent member 110 on which the polarization separating film 140 is formed.

In the polarization conversion element 102 of the modified example of the first embodiment, for example, as shown in FIG. is directly formed, and an antireflection film 181 is formed on the side surface 140c of the polarization separation film 140. As shown in FIG. The side surface 160e of the retardation plate 160 abuts on the side surface 181c of the antireflection film 181, and the retardation plate 160 composed of a plurality of inorganic columns 162 extending along the growth direction D ₁₆₂ is directly formed on the side surface 181c by oblique vapor deposition. formed. An antireflection film 182 is formed on the side surface 160c of the retardation plate 160. As shown in FIG. On the other hand, the reflective film 150 is directly formed on the side surface 110e of the first translucent member 110 (not shown in FIG. 4), and the side surface of the reflective film 150 opposite to the side surface in contact with the first translucent member 110 is formed. , the second translucent member 120 is arranged so that the side surface 120c of the second translucent member 120 contacts. Then, from the rear to the front in the X direction, the second translucent member 120, the reflective film 150, the first translucent member 110, the polarization separation film 140, the antireflection film 181, the half-wave retardation plate 160, and the reflective film. A basic stack consisting of the prevention film 182 is formed.

In the polarization conversion element 102 of the modified example of the first embodiment, the antireflection film 181 and the second translucent member 120 are adhered with an adhesive 190 . As in the first embodiment, when the adhesive 190 penetrates into the inorganic columnar bodies 162 of the retardation plate 160, the polarization conversion efficiency of the retardation plate 160 decreases. Therefore, in the polarization conversion element 102 of the modified example of the first embodiment, the antireflection film 182 prevents the S-polarized light WL _S converted by the half-wave retardation plate 160 from being reflected by the second translucent member 120 . In addition to the role of preventing this, the role of preventing the adhesive 190 from penetrating into the plurality of inorganic columnar bodies 162 of the retardation plate 160 is played.

As described above, in the polarization conversion element 102 of the modified example of the first embodiment, among the basic laminates adjacent to each other in the X direction, the antireflection film 182 of the lower basic laminate and the second basic laminate of the upper basic laminate An adhesive 190 is interposed between it and the translucent member 120 . In the polarization conversion element 102 of the first embodiment, the retardation plate 160 is formed on the second translucent member 120 as a substrate separate from the polarization separation film 140, whereas in the modification of the first embodiment, the polarized light In conversion element 102 , retardation plate 160 is formed on first translucent member 110 as the same substrate as polarization separation film 140 .

As described above, the polarization conversion elements 101 and 102 differ in the translucent member on which the retardation plate 160 is formed, but this difference is a difference in the manufacturing method of the polarization conversion elements. Since the polarization conversion element 102 of the modified example of the first embodiment has the same configuration as the polarization conversion element 101 of the first embodiment, it has the same effects as the polarization conversion element 101 of the first embodiment. That is, according to the polarization conversion element 102 of the modified example of the first embodiment, the generation of shadows caused by the edge portion is suppressed, and the birefringence in the retardation plate 160 and deterioration of the angle dependence of the polarization conversion characteristics are suppressed, A decrease in light utilization efficiency can be prevented. Further, according to the polarization conversion element 102 of the modified example of the first embodiment, in order to develop a desired phase difference, the conventional polarization conversion element having a zigzag-shaped or V-shaped columnar body or layer structure when viewed from the side is used. In comparison, the thickness of the half-wave retardation plate 160 can be reduced.

Further, in the polarization conversion element 101 of the first embodiment and the polarization conversion element 102 of the modified example of the first embodiment, an antireflection film 181 is provided between the half-wave retardation plate 160 and the polarization separation film 140, An antireflection film 182 is provided between the retardation plate 160 and the second translucent member 120 . As a result, the P-polarized WLP that has passed through the polarization separation film 140 enters the retardation plate 160 with high efficiency and undergoes polarization conversion. Also, the S-polarized light WLS after polarization conversion by the retardation plate 160 is guided to the second translucent member 120 with high efficiency. As a result, according to the polarization conversion element 101 of the first embodiment and the polarization conversion element 102 of the modified example of the first embodiment, compared to the case where the antireflection films 181 and 182 are not provided, the light utilization of the polarization conversion element 102 is reduced. Efficiency can be improved.

[Second embodiment]
Next, a second embodiment of the invention will be described with reference to FIGS. 5 to 7. FIG.
The projector and light source device of the second embodiment have the same configurations as the projector 1 and light source device 11 of the first embodiment, except that the polarization conversion element 132 described below is provided instead of the polarization conversion element 101 .
In each embodiment after the second embodiment, the same reference numerals as those of the above-described embodiments are given to the configurations common to the above-described embodiments such as the first embodiment, and descriptions thereof are omitted.

The polarization conversion element 132 of the second embodiment includes a plurality of first light-transmitting members 110, a plurality of second light-transmitting members 120, a plurality of light shielding films 130, a plurality of polarization separating films 140, and a plurality of It includes a reflective film 150 , a plurality of retardation plates 160 , and a plurality of antireflection films 181 and 182 . FIG. 5 is a schematic configuration diagram showing an enlarged region corresponding to the region R10 shown in FIG. 2 of the polarization conversion element 101 of the first embodiment in the polarization conversion element 132 of the second embodiment. As shown in FIG. 5 , in the polarization conversion element 132 , the half-wave retardation plate (oblique deposition film) 160 includes a first columnar structure film 165 and a second columnar structure film 166 .

The first columnar structure film 165 is an oblique deposition film having a plurality of inorganic columns (inorganic material) 171 . The plurality of inorganic columnar bodies 171 are arranged side by side along the Z direction. Each inorganic columnar body 171 is formed by oblique vapor deposition on the side surface 160 e of the retardation plate 160 . The growth direction D171 of the plurality of inorganic columnar bodies 171, that is, the columnar core direction of the inorganic columnar bodies 171 is one direction substantially parallel to the X direction, is inclined with respect to the side surface 160e of the retardation plate 160, and is polarized light separation. It is perpendicular to the traveling direction D _WL of the P-polarized light WL _P that is transmitted through the film 140 .

The second columnar structure film 166 is directly laminated on the side surface 165c of the first columnar structure film 165 and is an oblique deposition film having a plurality of inorganic columns (inorganic materials) 172 . The plurality of inorganic columnar bodies 172 are arranged side by side along the Z direction. Each inorganic columnar body 172 is formed by oblique vapor deposition on the side surface 165 c of the first columnar structure film 165 . The growth direction D172 of the plurality of inorganic columnar bodies 172, that is, the columnar core direction of the inorganic columnar bodies 172 is one direction substantially parallel to the X direction, and the traveling direction D of the _P -polarized light WLP transmitted through the polarization separation film 140. It is oriented perpendicular to _WL .

The inorganic columnar bodies 171 and 172 are made of crystal, for example, like the inorganic columnar body 162 described in the first embodiment.

When the second columnar structure film 166 is viewed from the growth directions D ₁₇₁ and D ₁₇₂ , the optical axis azimuth angle of the second columnar structure film 166 is 40° to 60° with respect to the optical axis azimuth angle of the first columnar structure film 165 . ° are arranged in a staggered manner. The deviation of the optical axis azimuth angle between the first columnar structure film 165 and the second columnar structure film 166 is at least within the range of 40° to 60°, preferably within the range of 45° to 55°. , is most preferably 54.7° as can be seen from geometrical calculations.

FIG. 6 is a schematic diagram for explaining the relative relationship between the azimuth angles of the optical axes of the first columnar structure film 165 and the second columnar structure film 166. As shown in FIG. For example, the azimuth angle _θ1 of the optical axis of the _{first columnar} structure film 165 is the X direction, i.e. 6 can be about 22.5 degrees clockwise with respect to the X-axis. On the other hand, the azimuth angle θ2 of the optical axis of the _second columnar structure film 166 can be about 67.5° clockwise with respect to the X direction when viewed along the traveling direction _DWL . can. Since the relative relationship between the azimuth angles θ ₁ and θ ₂ is established in this way, the _P -polarized light WLP traveling through the first columnar structure film 165 and the second columnar structure film 166 in sequence has λ/2 (half wavelength). That is, a phase difference of π is generated. For example, when the material of the first columnar structure film 165 and the second columnar structure film 166 is crystal, the difference between the azimuth angles θ ₁ and θ ₂ is 54.7° when viewed from the growth directions D ₁₇₁ and D ₁₇₂ . corresponds to Therefore, the difference in the optical axis azimuth angles of the first columnar structure film 165 and the second columnar structure film 166 when viewed from the growth directions D ₁₇₁ and D ₁₇₂ is It is appropriately set in consideration of the characteristics of the inorganic material of these columnar structure films, the wavelength range of the white light WL, and the like so that the phase difference imparted to the P-polarized light WL _P passing therethrough is λ/2.

A growth direction D171 in the first columnar structure film ₁₆₅ and a growth direction _D172 in the second columnar structure film 166 form a direction (vertical direction) D120 perpendicular to the side surfaces 120c and 120e of the second translucent member 120. The angle β is 45° when viewed from the Y direction. For example, in a conventional polarization conversion element having a zigzag-shaped or V-shaped columnar body or layered structure in a side view, such as the polarization conversion element disclosed in the above-mentioned Patent Document 2, one of the alternately switched growth directions If the growth direction is tilted by 45° with respect to the direction D120 of the second translucent member 120 when viewed from the Y direction, the other growth direction overlaps the traveling direction _DWL of the _P -polarized light WLP. Therefore, compared to the retardation plate 160 of the second embodiment, the thickness of the conventional retardation plate having a zigzag-shaped or V-shaped columnar body or layered structure when viewed from the side is greater than the thickness of the retardation plate 160 in the growth direction overlapping the traveling direction _DWL . large according to According to the polarization conversion element 132 including the retardation plate 160 of the second embodiment, in order to express the same retardation, the thickness of the retardation plate is greater than that of the polarization conversion element including the conventional retardation plate described above. is small.

In the polarization conversion element 132 of the second embodiment described above, the plurality of first light-transmitting members 110, the plurality of second light-transmitting members 120, the plurality of light shielding films 130, and the plurality of polarization separating films 140 , a plurality of reflective films 150, and a plurality of retardation plates 160, the incident non-polarized white light WL is converted into S-polarized WL _S , and the S-polarized WL _S is emitted from the surface 101b, which is the exit surface. can do. According to the polarization conversion element 132 of the second embodiment, since the retardation plate 160 includes the plurality of inorganic columns 171 and 172, heat resistance and light resistance can be improved compared to the case of including a dielectric multilayer film. . According to the polarization conversion element 132 of the second embodiment, shadows caused by edge portions are suppressed, deterioration of birefringence in the retardation plate 160 and angle dependence of polarization conversion characteristics is suppressed, and light utilization efficiency is reduced. can be prevented. In addition, according to the polarization conversion element 132 of the second embodiment, in order to develop a desired phase difference, compared to a conventional polarization conversion element having a zigzag-shaped or V-shaped columnar body or layered structure when viewed from the side, By reducing the thickness of the half-wave retardation plate 160, the manufacturing cost can be suppressed and the quality can be improved.

In addition, in the polarization conversion element 132 of the second embodiment, the half-wave retardation plate 160 has the growth direction D ₁₇₁ perpendicular to the traveling direction D _WL of the _P -polarized light WLP from the polarization separation film 140 . A first columnar structure film 165 and a second columnar structure film 166 stacked on the first columnar structure film 165 and having a growth direction D ₁₇₂ perpendicular to the traveling direction _DWL are provided. The second columnar structure film 166 is arranged with the optical axis azimuth angle shifted from the first columnar structure film 165 by 40° to 60°.

FIG. 7 is a graph showing an example of the polarization conversion efficiency of the polarization conversion element 132 of the second embodiment with respect to the polarization conversion element 101 of the first embodiment. In the calculation of the graph of FIG. 7, the material of the inorganic columnar bodies 171 and 172 was assumed to be quartz. As shown in FIG. 7, only one of the first columnar structure film 165 and the second columnar structure film 166 has the highest polarization conversion efficiency of 90%, and at least one of 450 nm and 650 nm. The polarization conversion efficiency at the wavelength is lower than the highest polarization conversion efficiency by 5% or more, and the wavelength band with high polarization conversion efficiency is narrow, that is, the narrow band. However, if the first columnar structure film 165 and the second columnar structure film 166 are used in combination, the wavelength bands of high polarization conversion efficiency are appropriately shifted from each other. The compensated retardation plate 160 as a whole has a wide wavelength band with high polarization conversion efficiency, that is, a wide band.

According to the configuration of the polarization conversion element 132 of the second embodiment described above, the first columnar structure film 165 and the second columnar structure film 166 are used. If the wavelength range with high polarization conversion efficiency is different in the columnar structure film 166, as shown in FIG. The polarization conversion efficiency in the low wavelength range is compensated by the other columnar structure film. In other words, according to the polarization conversion element 132 of the second embodiment, a wavelength region having a higher polarization conversion efficiency than the polarization conversion element 101 of the first embodiment having only one type of inorganic columnar body (columnar structure film) 162 can be obtained. It is possible to ensure a wide range and achieve achromaticity and broadband.

Note that in the polarization conversion element 132 of the second embodiment, the first columnar structure film 165 and the second columnar structure film 166 are second light-transmitting members different from the first light-transmitting member 110 on which the polarization separation film 140 is formed. However, as in the modified example of the first embodiment, the first columnar structure film 165 and the second columnar structure film 166 are the first light-transmitting films on which the polarization separation film 140 is formed. It may be obliquely deposited on the material member 110 .

Further, according to the configuration of the polarization conversion element 132 of the second embodiment described above, the second columnar structure film 166 is arranged such that the optical axis azimuth angle is shifted from the first columnar structure film 165 by 40° to 60°. Therefore, when viewed from the traveling direction _DWL of the _P -polarized light WLP transmitted through the polarization separation film 140 and incident on the retardation plate 160, the difference in the azimuth angle of the optical axis due to the two types of columnar structure films is π That is, it corresponds to λ/2, and a desired phase difference, that is, a half-wave phase difference is given to the _P -polarized light WLP. As a result, it is possible to prevent the accuracy of polarization conversion in the polarization conversion element 132 from being lowered.

According to the configuration of the polarization conversion element 132 of the second embodiment described above, the first translucent member 110 having the polarization separation film 140 laminated thereon, the first columnar structure film 165 and the second columnar structure film 166 are obliquely deposited. and the second translucent member 120 laminated by the adhesive 190 is adhesively fixed. As a result, in the polarization conversion element 132 of the second embodiment, the first basic laminate composed of the first translucent member 110 laminated with the polarization separation film 140, the first columnar structure film 165, and the second columnar structure A second basic laminate composed of the second light-transmitting member 120 laminated with the film 166 can be individually manufactured, and these basic laminates can be adhesively fixed, and can be easily manufactured.

[Third embodiment]
Next, a third embodiment of the invention will be described with reference to FIG.
The projector and light source device of the third embodiment have the same configuration as the projector 1 and light source device 11 of the first embodiment, except that the polarization conversion element 101 is replaced with the polarization conversion element 133 described below.

The polarization conversion element 133 of the third embodiment includes a plurality of first light-transmitting members 110, a plurality of second light-transmitting members 120, and a plurality of light shielding films 130 similar to the polarization conversion element 132 of the second embodiment. , a plurality of polarization separation films 140 , a plurality of reflection films 150 , a plurality of retardation plates 160 , a plurality of antireflection films 181 and 182 , and further adhesive penetration prevention films 195 and 196 . FIG. 8 is an enlarged schematic configuration diagram of a region corresponding to the region R10 shown in FIG. 2 of the polarization conversion element 101 of the first embodiment in the polarization conversion element 133 of the third embodiment. As shown in FIG. 8 , the half-wave retardation plate (oblique deposition film) 160 of the polarization conversion element 133 includes a first columnar structure film 165 and a second columnar structure film 166 .

The adhesive permeation prevention film 195 is formed directly on the side surface 165c of the first columnar structure film 165 and laminated on the first translucent member 110 as the same base material as the polarization separation film 140 and the first columnar structure film 165. ing. The adhesive permeation prevention film 196 is formed directly on the side surface 166 e of the second columnar structure film 166 and laminated on the second translucent member 120 as a base material different from the polarization separation film 140 and the first columnar structure film 165 . It is In the polarization conversion element 133 of the third embodiment, the adhesive permeation prevention films 195 and 196 are adhered to each other with an adhesive 190 . That is, the adhesive 190 is interposed between the adhesive permeation prevention film 195 and the adhesive permeation prevention film 196 .

The adhesive permeation prevention films 195 and 196 prevent the permeation of the adhesive 190 into the first columnar structure film 165 and the second columnar structure film 166, which are likely to be infiltrated by foreign matter or liquid due to gaps between the columnar bodies. The material of the adhesive permeation prevention films 195 and 196 is selected based on the material of the adhesive 190 as a material having an excellent function of preventing permeation of the adhesive 190, such as SiO ₂ or silicon nitride (Si ₃ N ₄ ). is.

In the polarization conversion element 133 of the third embodiment described above, the plurality of first light-transmitting members 110, the plurality of second light-transmitting members 120, the plurality of light shielding films 130, and the plurality of polarization separation films 140 , a plurality of reflective films 150 and a plurality of retardation plates 160 . In the polarization conversion element 133 of the third embodiment, the half-wave retardation plate 160 is arranged such that the growth directions D ₁₇₁ and D ₁₇₂ are orthogonal to the traveling direction D _WL of the _P -polarized light WLP from the polarization separation film 140 . A first columnar structure film 165 and a second columnar structure film 166 are provided. In addition, the second columnar structure film 166 is arranged with an optical axis azimuth angle of 40° to 60° with respect to the first columnar structure film 165, and the P-polarized light WL _P transmitted through the polarization splitting film 140 is arranged in the first direction. A phase difference of λ/2 is given by the columnar structure film 165 and the second columnar structure film 166 . Therefore, according to the polarization conversion element 133 of the third embodiment, similarly to the polarization conversion element 132 of the second embodiment, shadows caused by edge portions are suppressed, and birefringence and polarization conversion in the retardation plate 160 are suppressed. It is possible to suppress the deterioration of the angle dependence of the characteristics and prevent the deterioration of the light utilization efficiency. In addition, according to the polarization conversion element 133 of the third embodiment, the thickness of the half-wave retardation plate 160 is reduced compared to the conventional polarization conversion element having a zigzag-shaped or V-shaped columnar body or layered structure when viewed from the side. It can be made smaller, reducing manufacturing costs and improving quality. Furthermore, according to the polarization conversion element 133 of the third embodiment, compared to the polarization conversion element 101 of the first embodiment having only the inorganic columnar bodies 162, a wide wavelength range with high polarization conversion efficiency is ensured, and achromatic and Broadband can be achieved.

Further, in the polarization conversion element 133 of the third embodiment, the first columnar structure film 165 is arranged on the polarization separation film 140 of the first translucent member 110, and the second columnar structure film 166 is the second translucent member. It is located on member 120 . The first translucent member 110 and the second translucent member 120 are fixed with an adhesive 190 via adhesive permeation prevention films 195 and 196 . In this configuration, the polarization separation film 140, the antireflection film 181, the first columnar structure film 165, and the adhesive penetration prevention film 195 are laminated on the side surface 110c of the first translucent member 110 as the first basic laminate. ing. On the other hand, as a second basic laminate, an antireflection film 182, a second columnar structure film 166, and an adhesive penetration prevention film 196 are laminated on the side surface 120e of the second translucent member 120. FIG. Therefore, the first basic laminate and the second basic laminate can be produced independently and individually.

For example, in the polarization conversion element 133 of the third embodiment, the steps of obliquely depositing the first columnar structure film 165 on the first translucent member 110 having the polarization separation film 140 and the antireflection film 181 laminated on the side surface 110c; This requires time and a process and time for obliquely depositing the second columnar structure film 166 thereon. According to the polarization conversion element 133 of the third embodiment, the first basic laminate and the second basic laminate are produced in parallel, and the first columnar structure film 165 and the second columnar structure film 166 are formed. Parallel oblique deposition can reduce manufacturing yield and quality risk.

Further, since the polarization conversion element 133 of the third embodiment includes the adhesive permeation prevention films 195 and 196 with the adhesive 190 interposed therebetween, each of the first columnar structure film 165 and the second columnar structure film 166 of the adhesive 190 can be prevented from penetrating into the first columnar structure film 165 and the second columnar structure film 166, and deterioration of birefringence and polarization conversion characteristics in each of the first and second columnar structure films 165 and 166 can be prevented. As a result, the polarization conversion element 133 of the third embodiment can satisfactorily convert the _P -polarized light WLP transmitted through the polarization separating film 140 into the _S -polarized light WLS.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the scope of the claims. Transformation and change are possible. In addition, the constituent elements of multiple embodiments can be combined as appropriate.

For example, in the polarization conversion elements 101, 102, 112, and 113 of each of the embodiments described above, crystal was exemplified as an inorganic material forming each of the inorganic columnar body 162, the first columnar structure film 165, and the second columnar structure film 166. However, inorganic materials other than quartz may be used. When an inorganic material other than quartz is used as the inorganic material constituting each of the first columnar structure film 165 and the second columnar structure film 166, the azimuth angle of the optical axis by the first columnar structure film 165 and the second columnar structure film 166 The angle β can be adjusted according to the characteristics of the inorganic material so that the deviation of the _P -polarized light WLP transmitted through the polarization separating film 140 has a phase difference of λ/2.

Further, as the light source device 11 of the first embodiment, a device including the light source 15, the integrator optical system 31, the polarization conversion element 100, and the superimposing lens 33A was exemplified, but the device is not limited to this device. Also, the superimposing lens 33A may be omitted. For example, the light source device of the present invention may be composed of a light source such as a white lamp, a plurality of lens systems including microlenses, and the polarization conversion element of the present invention.

A light source device according to an aspect of the present invention may have the following configuration.
A polarization conversion element according to one aspect of the present invention includes a first translucent member having an incident surface on which light is incident, a pair of first inclined surfaces, and an exit surface from which light exits, and a pair of second inclined surfaces. Between a second translucent member having an exit surface from which light exits, and one first inclined surface of the pair of first inclined surfaces and one second inclined surface of the pair of second inclined surfaces and reflects the first polarized light, which is one of the polarized components of the light incident on the first translucent member, and transmits the second polarized light, which is the other polarized component of the light incident on the first translucent member. A polarization separation film that separates light incident on the member, and a polarization separation film that is disposed on the other first inclined surface of the pair of first inclined surfaces so that the first polarized light reflected by the polarization separation film is emitted from the first translucent member. A reflective film that reflects on the surface, and is disposed between the polarization separation film and one of the second inclined surfaces, converts the second polarized light transmitted through the polarization separation film into the first polarized light, and the second translucent member. and a half-wave retardation plate that guides light to the half-wave retardation plate. This is an obliquely deposited film.

In the polarization conversion element according to one aspect of the present invention, the obliquely deposited film includes a first columnar structure film whose growth direction is perpendicular to the traveling direction of the second polarized light from the polarization separation film; Laminated on the columnar structure film, the growth direction is perpendicular to the traveling direction of the second polarized light from the polarization separation film, and the optical axis azimuth angle is shifted from the first columnar structure film by 40° to 60° and a disposed second columnar structure film.

In the polarization conversion element according to one aspect of the present invention, the obliquely deposited film includes a first columnar structure film whose growth direction is perpendicular to the traveling direction of the second polarized light from the polarization separation film; Laminated on the columnar structure film, the growth direction is perpendicular to the traveling direction of the second polarized light from the polarization separation film, and the optical axis azimuth angle is shifted from the first columnar structure film by 40° to 60° and a disposed second columnar structure film.

In the polarization conversion element of one aspect of the present invention, the first translucent member laminated with the polarization separation film and the second translucent member laminated with the oblique vapor deposition film may be adhesively fixed.

In one aspect of the polarization conversion element of the present invention, the first columnar structure film is arranged on the polarization separating film of the first translucent member, and the second columnar structure film is arranged on the second translucent member. Alternatively, the first columnar structure film and the second columnar structure film may be fixed with an adhesive via an adhesive permeation prevention film.

In one aspect of the polarization conversion element of the present invention, an antireflection film is provided between the half-wave retardation plate and the polarization separation film and between the half-wave retardation plate and the second translucent member. may be

A light source device according to one aspect of the present invention may have the following configuration.
A light source device of one aspect of the present invention includes a light source and the polarization conversion element of the above aspect of the present invention.

A projector according to one aspect of the present invention may have the following configuration.
A projector according to one aspect of the present invention includes the light source device according to the above aspect of the present invention, an optical modulator that modulates light from the light source device according to image information, and a projector that projects the light modulated by the optical modulator. and an optical device.

DESCRIPTION OF SYMBOLS 1... Projector 11... Light source device 101, 102, 132, 133... Polarization conversion element 110... First translucent member 120... Second translucent member 140... Polarization separating film 150... Reflecting film, 160... Retardation plate (half-wave retardation plate), 162... Inorganic columnar body (inorganic material), 165... First columnar structure, 166... Second columnar structure.

Claims (8)

a first translucent member having an incident surface on which light enters, a pair of first inclined surfaces, and an exit surface from which light exits;
a second translucent member having a pair of second inclined surfaces and an exit surface from which light exits;
Light that is placed between one of the pair of first inclined surfaces and one of the pair of second inclined surfaces and enters the first translucent member a polarization separation film that reflects the first polarized light, which is one of the polarized components, and transmits the second polarized light, which is the other polarized component, thereby separating the light incident on the first translucent member;
a reflecting film disposed on the other first inclined surface of the pair of first inclined surfaces and reflecting the first polarized light reflected by the polarization separation film to the exit surface of the first translucent member;
is disposed between the polarization separation film and the one second inclined surface, converts the second polarized light transmitted through the polarization separation film into first polarized light, and guides the light to the second translucent member; a half-wave retardation plate for
with
The half-wave retardation plate is an oblique deposition film having an inorganic material whose growth direction is orthogonal to the traveling direction of the second polarized light that passes through the polarization separation film,
Polarization conversion element. The oblique deposition film is
a first columnar structure film, the growth direction of which is orthogonal to the traveling direction of the second polarized light from the polarization separation film;
Laminated on the first columnar structure film, the growth direction is perpendicular to the traveling direction of the second polarized light from the polarization separation film, and the optical axis azimuth angle is 40 with respect to the first columnar structure film. a second columnar structure film arranged at an angle of ~60°;
comprising
The polarization conversion element according to claim 1. The angle formed by the growth direction and the vertical direction of the second translucent member is 45°.
The polarization conversion element according to claim 2. The first translucent member laminated with the polarization separating film and the second translucent member laminated with the oblique vapor deposition film are adhesively fixed.
4. The polarization conversion element according to claim 2 or 3. the first columnar structure film is disposed on the polarization separating film of the first translucent member;
the second columnar structure film is disposed on the second translucent member;
The first columnar structure film and the second columnar structure film are fixed with an adhesive via an adhesive penetration prevention film,
The polarization conversion element according to claim 4. An antireflection film is provided between the half-wave retardation plate and the polarization separation film and between the half-wave retardation plate and the second translucent member.
The polarization conversion element according to any one of claims 1 to 5. a light source;
a polarization conversion element according to any one of claims 1 to 6 and after, on which light from the light source is incident;
comprising
Light source device. A light source device according to claim 7;
a light modulating device that modulates light from the light source device according to image information;
a projection optical device that projects the light modulated by the light modulation device;
comprising
projector.

Images