JP2009229560A - Method of manufacturing optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical device having a plurality of optical modulating elements, a plurality of exit-side polarizers, and a color synthesizing optical device unified into one body and allows focus adjustment of each optical modulating element to be easily performed. <P>SOLUTION: The method of manufacturing an optical device 5 includes: an optical device holding step of holding an optical modulating element 51, an exit-side polarizer 53, and a color synthesizing optical device 54 in an initial state of being in close contact with each other; a focus adjustment step of changing relative positions of prisms 531 and 532 constituting the exit-side polarizer 53, along inclination directions D1 and D2 of slopes 531B and 532B of the prisms 531 and 532 to adjust the positions in an optical axis direction in the optical modulating element 51; and a fixing step of fixing the optical modulating element 51 and the exit-side polarizer 53 to the color synthesizing optical device 54. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical device.

2. Description of the Related Art Conventionally, a projector that includes a light source device, a light modulation element that modulates a light beam emitted from the light source device according to image information to form image light, and a projection optical device (projection lens) that magnifies and projects the image light It has been known.
In such projectors, polarizing elements that transmit predetermined linearly polarized light and remove other light beams from the incident light beam are usually arranged on the light beam incident side and light beam emission side of the light modulation element (liquid crystal panel). (For example, see Patent Document 1).
In the projector described in Patent Document 1, a reflection-type polarizing element is used as the exit-side polarizing element disposed on the light beam exit side of the liquid crystal panel, improving the light resistance and heat resistance of the exit-side polarizing element, and An unnecessary light flux reflected by the side polarizing element is not incident on the liquid crystal panel.
Specifically, the exit side polarization element includes a first prism having a triangular cross section having a light beam incident side end surface orthogonal to the optical axis of the incident light beam, and an exit side inclined surface inclined with respect to the light beam incident side end surface; A second prism having a triangular cross section integrated with the first prism, having a light beam exit side end surface parallel to the side end surface, and an incident side inclined surface that is inclined with respect to the light beam exit side end surface and faces the exit side inclined surface; And a reflective polarizing plate interposed between the inclined surfaces. Then, the unnecessary light beam reflected by the reflective polarizing plate is totally reflected at the light beam incident side end surface of the first prism and proceeds in a direction avoiding the liquid crystal panel.

International Publication WO01 / 055778

By the way, in a so-called three-plate type optical device in which three liquid crystal panels are provided and each color light modulated by each liquid crystal panel is synthesized by a color synthesis optical device (cross dichroic prism) to form a color image, a projector is used. In consideration of handling properties such as when assembling, it is preferable that the exit-side polarizing element and the liquid crystal panel are integrally assembled with the color synthesizing optical device.
In a projector equipped with such an optical device, in order to obtain a clear image, it is necessary to move each liquid crystal panel in the optical axis direction and position each liquid crystal panel at the back focus position of the projection lens (focus adjustment). is there.
However, when the exit-side polarizing element described in Patent Document 1 is adopted in the above-described three-plate optical device, there are the following problems.
In the exit side polarizing element described in Patent Document 1, since the first prism, the second prism, and the reflective polarizing plate are integrated in advance, the distance between the light incident side end face and the light exit side end face is defined. Will be. When the exit-side polarizing element and the liquid crystal panel are assembled integrally with the color combining optical device, the liquid crystal panel is fixed to the light-incident side end face of the exit-side polarizing element. The separation position in the direction is defined in advance. That is, since the separation position of the liquid crystal panel in the optical axis direction with respect to the color synthesis optical device is defined in advance, there is a problem that it is difficult to adjust the focus of each liquid crystal panel.

  An object of the present invention is to provide an optical device manufacturing method capable of easily adjusting the focus of each light modulation element in an optical device in which a plurality of light modulation elements, a plurality of exit-side polarization elements, and a color synthesis optical device are integrated. Is to provide.

  The manufacturing method of the present invention combines a plurality of light modulation elements that form image light by modulating a plurality of color lights according to image information for each color light, and each image light formed by the plurality of light modulation elements. A method of manufacturing an optical device comprising: a color combining optical device, and a plurality of light modulation devices and a plurality of exit-side polarization elements respectively disposed between the plurality of light modulation devices and the color combining optical device. The element is in parallel with the light beam incident side end surface, a first prism having a light beam incident side end surface that is in contact with the light modulation element and that receives the image light, and an exit side inclined surface that is inclined with respect to the light beam incident side end surface. A second prism having a light-emitting side end surface that is in contact with the color combining optical device, and an incident-side inclined surface that is inclined with respect to the light-emitting side end surface and is parallel to the output-side inclined surface; Provided on the incident side inclined surface The first linearly polarized light transmitted through the first prism is transmitted and introduced into the second prism, and the second linearly polarized light whose polarization direction is orthogonal to the first linearly polarized light is transmitted. A polarizing element body that reflects toward the first prism, and the manufacturing method includes an optical device that holds the light modulation element, the emission-side polarizing element, and the color combining optical device in an initial state in close contact with each other. A holding step, a focus adjusting step of changing a relative position of each prism along the inclination direction of each inclined surface, and adjusting a position in the optical axis direction of the color light in the light modulation element; and the color synthesizing optical device A fixing step of fixing the light modulation element and the exit-side polarization element.

In the present invention, in the optical device holding step, the light modulation element, the first prism, the second prism, and the color synthesizing optical device are held in the initial state of being in close contact with each other from the light beam incident side. Then, in the focus adjustment step, the relative position of each prism is changed along the inclination direction of each inclined surface of each prism, so that the light beam incident side end surface and the light beam emission side end surface of the exit side polarization element are separated in the optical axis direction. The dimension is changed, that is, the position in the optical axis direction of the light modulation element that is in close contact with the light incident side end face of the exit side polarization element is adjusted. After positioning each light modulation element at a predetermined position with respect to the color synthesis optical device, the optical device is manufactured by fixing the light modulation element and the exit side polarization element to the color synthesis optical device in the fixing step.
As described above, in the exit side polarizing element, the first prism and the second prism are not integrated in advance, but are integrated when the optical device is manufactured. Accordingly, the focus adjustment of the light modulation element can be easily performed by changing the relative position of each prism along the tilt direction. Therefore, each light modulation element is surely positioned at the back focus position of the projection optical apparatus, and a clear image can be obtained by incorporating the optical apparatus into the projector.

  The manufacturing method of the present invention combines a plurality of light modulation elements that form image light by modulating a plurality of color lights according to image information for each color light, and each image light formed by the plurality of light modulation elements. A method of manufacturing an optical device, comprising: a color combining optical device, and a plurality of light modulation elements and a plurality of exit side polarization elements disposed between the plurality of light modulation elements, and the exit side polarization The element has a light beam incident side end face that is in contact with the light modulation element and receives the image light, and an emission side inclined face that is inclined with respect to the light flux incident side end face, and the light flux incident side end face and the emission side end face A first prism arranged so that a separation dimension of the color light in the optical axis direction becomes smaller along a first direction orthogonal to the optical axis, and the color combining optics parallel to the light incident side end surface End surface of light beam exiting contact with the apparatus, and the light beam An incident-side inclined surface that is inclined with respect to the exit-side end surface, and is arranged so that a separation dimension in the optical axis direction between the light-beam exit-side end surface and the incident-side inclined surface decreases along the first direction. A second prism, a third prism having a first opposing surface interposed between the prisms and parallel to the exit-side inclined surface, and a second opposing surface parallel to the incident-side inclined surface; The first linearly polarized light is transmitted through the first prism and is introduced into the third prism, and the direction of polarization is the first direction. A polarizing element body that reflects the second linearly polarized light orthogonal to the linearly polarized light toward the first prism, and the manufacturing method includes the light modulating element, the exit-side polarizing element, and the color combining optics. In the initial state where the devices are in close contact with each other Holding the optical device, and moving the third prism forward and backward along the first direction with respect to the first prism and the second prism to adjust the position of the optical modulation element in the optical axis direction And a fixing step of fixing the light modulation element and the exit-side polarization element to the color synthesizing optical device.

In the present invention, in the optical device holding step, the light modulation element, the first prism, the third prism, the second prism, and the color synthesizing optical device are held in the initial state of being in close contact with each other from the light beam incident side. Then, in the focus adjustment step, the third prism moves forward and backward along the first direction with respect to the first prism and the second prism while maintaining the close contact between the first prism, the second prism, and the third prism. Let Here, the first prism is disposed so that the separation dimension in the optical axis direction between the light incident side end surface and the exit side inclined surface becomes smaller along the first direction. The same applies to the second prism. In other words, the third prism has a wedge shape in which the distance between the first facing surface and the second facing surface in the optical axis direction increases along the first direction. For this reason, in the focus adjustment process, the first prism and the second prism are closely separated in the optical axis direction in conjunction with the forward and backward movement along the first direction of the third prism, so that the light flux is incident on the exit side polarization element. The separation distance in the optical axis direction between the side end surface and the light beam exit side end surface is changed, that is, the position in the optical axis direction of the light modulation element in close contact with the light beam incident side end surface in the exit side polarization element is adjusted. After positioning each light modulation element at a predetermined position with respect to the color synthesis optical device, the optical device is manufactured by fixing the light modulation element and the exit side polarization element to the color synthesis optical device in the fixing step.
As described above, the exit-side polarizing element includes the third prism in addition to the first prism and the second prism, and the prisms are not integrated in advance but are integrated when the optical device is manufactured. Accordingly, the focus adjustment of the light modulation element can be easily performed by moving the third prism forward and backward along the first direction. Therefore, each light modulation element is surely positioned at the back focus position of the projection optical apparatus, and a clear image can be obtained by incorporating the optical apparatus into the projector.

In the manufacturing method of the present invention, the plurality of exit side polarization elements are formed such that, in the initial state, the distance between the light incident side end face and the light exit side end face differs according to the corresponding color light. Is preferred.
By the way, as a general characteristic of a lens, the refractive index of each color is different. For this reason, the back focus position of the projection optical apparatus tends to be different depending on each color light.
In the present invention, since the plurality of exit-side polarizing elements are formed as described above, in the initial state, the separation dimensions in the optical axis direction of the respective light modulation elements with respect to the color synthesizing optical device are different. In this way, in the initial state, if the separation dimensions of the light beam incident side end surfaces and the light beam output side end surfaces of the plurality of emission side polarizing elements are designed according to each back focus position for each color light of the projection optical device, The light modulation elements are almost positioned at the respective back focus positions, and in the focus adjustment step, each light modulation element can be positioned at each back focus position only by fine adjustment. Therefore, the focus adjustment of each light modulation element can be performed more easily.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[Main components of the projector]
FIG. 1 is a diagram schematically showing a schematic configuration of a projector 1 in the first embodiment.
The projector 1 modulates a light beam emitted from a light source according to image information to form image light, and enlarges and projects the formed image light on a screen (not shown). As shown in FIG. 1, the projector 1 is roughly configured by an optical unit 3, a projection lens 4 as a projection optical device, and an exterior housing 2 that houses the optical unit 3 and the projection lens 4 and constitutes an exterior. ing.
Although not specifically illustrated, each of the projector 1 and the cooling unit provided with a cooling fan or the like for cooling the inside of the projector 1 in a space other than the optical unit 3 and the projection lens 4 in the exterior housing 2. It is assumed that a power supply device that supplies power to the constituent members, a control device that controls operations of the constituent members of the projector 1, and the like are arranged.

The optical unit 3 optically processes the light beam emitted from the light source device 31 under the control of the control device to form image light corresponding to the image information. This optical unit 3 has a light source device 31, an illumination optical device 32, a color separation optical device 33, a relay optical device 34, an optical device 5, and these optical components 31 to 34, 5 set therein. And an optical component casing 35 disposed at a predetermined position with respect to the illumination optical axis Ax.
As illustrated in FIG. 1, the light source device 31 includes a light source lamp 311, a reflector 312, and the like. In the light source device 31, the light beam emitted from the light source lamp 311 is aligned in the emission direction by the reflector 312, and is emitted toward the illumination optical device 32.

  As shown in FIG. 1, the illumination optical device 32 includes a first lens array 321, a second lens array 322, a polarization conversion element 323, and a superimposing lens 324. The light beam emitted from the light source device 31 is divided into a plurality of partial light beams by the first lens array 321 and forms an image in the vicinity of the second lens array 322. Each partial light beam emitted from the second lens array 322 is incident so that its central axis (principal ray) is perpendicular to the incident surface of the polarization conversion element 323, and approximately one type of linearly polarized light is generated by the polarization conversion element 323. Injected as light. A plurality of partial light beams emitted from the polarization conversion element 323 as linearly polarized light and passed through the superimposing lens 324 are superimposed on three liquid crystal panels 51 (to be described later) of the optical device 5.

As shown in FIG. 1, the color separation optical device 33 includes two dichroic mirrors 331 and 332 and a reflection mirror 333, and the dichroic mirrors 331 and 332 and the reflection mirror 333 emit the light from the illumination optical device 32. It has a function of separating a plurality of partial light beams into three color lights of red, green, and blue.
As shown in FIG. 1, the relay optical device 34 includes an incident side lens 341, a relay lens 343, and reflection mirrors 342 and 344, and color light separated by the color separation optical device 33, for example, red light, is supplied to the optical device 5. The liquid crystal panel 51R on the red light side which will be described later is guided.

The optical device 5 modulates the incident light beam according to image information to form image light.
A specific configuration of the optical device 5 will be described later.
The projection lens 4 is configured as a combined lens in which a plurality of lenses are combined, and enlarges and projects the image light emitted from the optical device 5 on the screen.

[Configuration of optical device]
FIG. 2 is an exploded perspective view schematically showing the configuration of the optical device 5.
As shown in FIG. 1 or FIG. 2, the optical device 5 includes a liquid crystal panel 51 as a light modulation element (a liquid crystal panel on the red light side is 51R, a liquid crystal panel on the green light side is 51G, and a liquid crystal panel on the blue light side is 51B. ), An incident-side polarizing element 52 disposed on the upstream side of the optical path of each liquid crystal panel 51, and an exit-side polarizing element 53 disposed on the downstream side of the optical path of each liquid crystal panel 51 (similar to the liquid crystal panel 51, red light). And a green light-side exit-side polarizing element 53G, and a blue-light-side exit-side polarizing element 53B), and a cross dichroic prism 54 as a color synthesizing optical device.
In addition, below, the structure of each optical component 51-54 is demonstrated in order from the light beam entrance side.

The incident side polarization element 52 transmits only linearly polarized light having a polarization direction substantially the same as the polarization direction aligned by the polarization conversion element 323. In the present embodiment, the incident-side polarizing element 52 is configured by a reflective polarizer, like a polarizing element body 533 described later.
As shown in FIG. 2, the liquid crystal panel 51 has a configuration in which liquid crystal, which is an electro-optical material, is hermetically sealed between a pair of rectangular substrates 511 and 512 made of glass or the like. Among these, the substrate 511 is a driving substrate for driving the liquid crystal, and includes a plurality of data lines arranged in parallel to each other, a plurality of scanning lines arranged in a direction orthogonal to the plurality of data lines, The pixel electrodes are arranged in a matrix corresponding to the intersections of the scanning lines and the data lines, switching elements such as TFTs (Thin Film Transistors), and drive units that drive the switching elements. The substrate 512 is a counter substrate that is disposed to face the substrate 511 at a predetermined interval, and has a common electrode to which a predetermined voltage Vcom is applied. Further, these substrates 511 and 512 are FPCs as circuit boards that are electrically connected to the control device and output predetermined drive signals to the scanning lines, the data lines, the switching elements, the common electrodes, and the like. A cable 513 is connected. By inputting a drive signal from the control device via the FPC cable 513, a voltage is applied between the predetermined pixel electrode and the common electrode, and the alignment state of the liquid crystal interposed between the pixel electrode and the common electrode Is controlled, and the polarization direction of the polarized light beam emitted from the incident side polarization element 52 is modulated.

  The exit-side polarizing element 53 transmits only the first linearly polarized light having a polarization direction orthogonal to the transmission axis of the incident-side polarizing element 52 out of the light flux emitted through the liquid crystal panel 51. As shown in FIG. 2, the exit side polarization element 53 includes a first prism 531, a second prism 532, and a polarization element body 533.

  The first prism 531 is composed of a triangular prism having a substantially right-angled triangular cross section, the light incident side end surface 531A is orthogonal to the illumination optical axis Ax, and the exit-side inclined surface 531B corresponds to the hypotenuse having a substantially right-angled triangular cross section. Is disposed in a state inclined with respect to a plane (light beam incident side end surface 531A) that is positioned on the light beam emission side and orthogonal to the illumination optical axis Ax.

  The second prism 532 is a triangular prism having the same shape and the same refractive index as the first prism 531. The second prism 532 has a light exit side end surface 532A orthogonal to the illumination optical axis Ax, and an incident side inclined surface 532B corresponding to a hypotenuse having a substantially right-angled section in cross section. It arrange | positions in the state parallel to 531B.

  The polarizing element body 533 is provided on the incident-side inclined surface 532B, and reflects the second linearly polarized light that transmits the first linearly polarized light and whose polarization direction is orthogonal to the first linearly polarized light. It consists of In the present embodiment, the polarizing element body 533 has a configuration in which a large number of fine linear ribs such as aluminum are formed in parallel on the incident-side inclined surface 532B, although not specifically illustrated. The polarizing element body 533 transmits linearly polarized light (first linearly polarized light) having a perpendicular polarization direction in the direction in which the linear rib extends, and linearly polarized light (secondly polarized light having a parallel polarization direction) Of linearly polarized light).

Each of the exit-side polarizing elements 53 was held in an initial state of being in close contact with each other at the time of manufacturing the optical device 5 described later (in the present embodiment, in the state of being in close contact with each other so as to have a rectangular parallelepiped shape as a whole). At this time, the light-incidence-side end surface 531A and the light-irradiation-side end surface 532A are formed to have different separation dimensions.
Specifically, the separation dimension of the light beam incident side end surface 531A and the light beam emission side end surface 532A in each exit side polarization element 53 is shown in FIG. 1 or FIG. 2 according to the back focus position corresponding to each color light of the projection lens 4. As shown, the exit-side polarizing element 53B, the exit-side polarizing element 53G, and the exit-side polarizing element 53R are formed so as to increase in order.

FIG. 3 is a diagram schematically showing the optical path of the light beam emitted from the exit side polarization element 53. Specifically, FIG. 3 is a longitudinal sectional view of the integrated exit side polarization element 53 after the optical device 5 is manufactured.
Then, the emission side polarization element 53 emits the light beam L1 through the liquid crystal panel 51 as described below, with the above-described configuration.
That is, as shown in FIG. 3, the light beam L1 is introduced into the first prism 531, and is separated into the first linearly polarized light L11 and the second linearly polarized light L12 by the polarizing element body 533.
The first linearly polarized light L <b> 11 passes through the polarization element body 533, is emitted through the second prism 532, and is introduced into the cross dichroic prism 54. At this time, the first linearly polarized light L11 travels in substantially the same direction as the traveling direction of the light beam L1.
On the other hand, the second linearly polarized light L12 is reflected by the polarizing element body 533 to the light beam incident side, and is incident on the light beam incident side end surface 531A. The second linearly polarized light L12 is totally reflected by the light beam incident side end surface 531A and is emitted from the end surface 531C intersecting the light beam incident side end surface 531A and the emission side inclined surface 531B of the first prism 531. That is, the second linearly polarized light L12 is emitted in a direction avoiding the liquid crystal panel 51 (upward in the present embodiment). Although not specifically shown, an antireflection film for preventing reflection of the second linearly polarized light L12 is formed on the end face 531C.

  The cross dichroic prism 54 combines the color lights transmitted through the exit-side polarization elements 53 to form image light (color image). The cross dichroic prism 54 has a substantially square shape in plan view in which four right angle prisms are bonded together, and two dielectric multilayer films are formed at the interface where the right angle prisms are bonded together. These dielectric multilayer films transmit the G-color light transmitted through the exit-side polarizing element 53G, and reflect the R and B-color lights transmitted through the exit-side polarizing elements 53R and 53B. In this way, the color lights are combined to form a color image.

  And each member 51-54 mentioned above is integrated in the state which mutually contact | adhered by the manufacturing method of the optical apparatus 5 shown below.

[Method for Manufacturing Optical Device]
FIG. 4 is a flowchart illustrating a method for manufacturing the optical device 5.
5 to 7 are views for explaining a method of manufacturing the optical device 5. Specifically, FIG. 5 is a diagram for explaining the focus adjustment process, and is a view of the optical device 5 as viewed from the side. FIG. 6 is a view for explaining the alignment adjustment process, and is a view of the optical device 5 as viewed from above. FIG. 7 is a view for explaining the alignment adjustment step as in FIG. 6, and is a view of the optical device 5 as viewed from the side.
First, the liquid crystal panel 51 is fixed to the light incident side end surface 531A of the first prism 531 with an adhesive or the like (step S1). Hereinafter, a unit in which the liquid crystal panel 51 and the first prism 531 are integrated will be described as the panel unit 6.
After step S1, the cross dichroic prism 54 is installed at a predetermined position in a manufacturing apparatus (not shown) (step S2).
After step S2, a photo-curing adhesive is applied to the light incident side end face 54A of the cross dichroic prism 54. Then, the second prism 532 is held on the alignment adjustment jig 100 (FIGS. 5 to 7) for adjusting the position of the liquid crystal panel 51 with respect to the cross dichroic prism 54, and a photo-curing adhesive is applied. The luminous flux emission side end surface 532A is brought into close contact with the luminous flux incident side end surface 54A (step S3).

After step S3, a photocurable adhesive is applied to the surplus portion where the polarizing element body 533 is not formed on the incident side inclined surface 532B. Then, the panel unit 6 was held in a focus adjustment jig 200 (FIGS. 5 to 7) for adjusting the position of the liquid crystal panel 51 with respect to the cross dichroic prism 54, and a photo-curing adhesive was applied. The exit side inclined surface 531B is brought into close contact with the incident side inclined surface 532B (step S4).
By the steps S2 to S4 described above, as shown in FIG. 5A, the first prism 531 and the second prism 532 have a rectangular parallelepiped shape as a whole, and the liquid crystal panel 51, the exit-side polarizing element 53, and the cross dichroic The prism 54 is held in an initial state in which the prisms 54 are in close contact with each other.
That is, steps S2 to S4 correspond to the optical device holding step according to the present invention.

After step S4, the position adjustment of the liquid crystal panel 51 with respect to the cross dichroic prism 54 is performed with the photo-curing adhesive in an uncured state as shown below.
First, a light beam for position adjustment is introduced into the liquid crystal panel 51 (step S5).
After step S5, the image light via the liquid crystal panel 51, the exit side polarization element 53, and the cross dichroic prism 54 is confirmed (step S6).
For example, the projection lens 4 is disposed on the downstream side of the optical path of the cross dichroic prism 54, and the projection lens 4 projects image light on the screen. Then, the projected image on the screen is confirmed. Alternatively, the projected image on the screen is captured by an imaging device such as a CCD (Charge Coupled Device) camera, and the captured image is confirmed on a monitor or the like.
Further, for example, image light that has passed through the cross dichroic prism 54 is directly captured by an imaging device such as a CCD camera, and the captured image is confirmed on a monitor or the like.

  In step S6, while confirming the projected image on the screen and the captured image of the monitor or the like, using the focus adjustment jig 200, as shown in FIG. 5B and FIG. Position where the panel unit 6 is moved along the inclined directions D1 and D2 of the inclined surfaces 531B and 532B with the joint surface between the 531B and the incident-side inclined surface 532B as a sliding surface, and the projected image and the captured image are brought into focus. (Step S7: Focus adjustment step). That is, by moving the panel unit 6 along the tilt directions D1 and D2, the separation dimension L (FIG. 5) between the light beam incident side end surface 531A and the light beam emission side end surface 532A is changed, in other words, the cross dichroic. The position along the illumination optical axis Ax of the liquid crystal panel 51 with respect to the prism 54 is changed, and the projection lens 4 is positioned at the back focus position (position where the projected image and the captured image are in focus).

  After step S7, while confirming the projected image and the captured image, using the respective adjustment jigs 100 and 200, as shown in FIG. 6 or FIG. 7, the light incident side end surface 54A of the cross dichroic prism 54 and the second end surface 54A. Using the joint surface of the prism 532 with the beam exit side end surface 532A as a sliding surface, the panel unit 6 together with the second prism 532 is moved in the horizontal direction D3, D4 and the vertical direction D5, D6 in a plane perpendicular to the illumination optical axis Ax. Then, the pixels in the projected image and the captured image are positioned at predetermined positions for matching the pixels of the liquid crystal panels 51 (step S8: alignment adjustment step).

After step S8, the photo-curing adhesive between the cross dichroic prism 54 and the second prism 532 and between the second prism 532 and the first prism 531 is cured by irradiating ultraviolet rays or the like, and the cross dichroic prism 54 is applied to the cross dichroic prism 54. On the other hand, the liquid crystal panel 51 and the exit side polarization element 53 are fixed (step S9: fixing step).
The optical device 5 is manufactured by performing the above steps on the three liquid crystal panels 51 and fixing the incident-side polarizing elements 52 to predetermined positions of the respective counter substrates 512 of the liquid crystal panels 51 with an adhesive or the like. Is done.

The first embodiment described above has the following effects.
In the present embodiment, the exit side polarization element 53 constituting the optical device 5 is not integrated with the first prism 531 and the second prism 532 in advance, but is integrated when the optical device 5 is manufactured. Accordingly, the focus adjustment of the liquid crystal panel 51 can be easily performed by moving the panel unit 6 with respect to the second prism 532 along the tilt directions D1 and D2. Therefore, each liquid crystal panel 51 is surely positioned at the back focus position of the projection lens 4, and if the optical device 5 is incorporated in the projector 1, a clear image can be obtained.

  Further, since each exit-side polarizing element 53 is formed so that the distance between the light incident side end surface 531A and the light exit side end surface 532A is different when held in the initial state, the cross dichroic prism 54 in the initial state. The separation dimension along the illumination optical axis Ax of each liquid crystal panel 51 is different. Accordingly, by designing the separation dimensions of the light beam incident side end surface 531A and the light beam output side end surface 532A of each emission side polarization element 53 according to each back focus position for each color light of the projection lens 4, in the initial state, Each liquid crystal panel 51 is positioned substantially at each back focus position. In the focus adjustment step S7, each liquid crystal panel 51 can be positioned at each back focus position only by fine adjustment. Therefore, the focus adjustment of each liquid crystal panel 51 can be performed more easily.

  Further, the alignment units 100 and 200 are used to move the panel unit 6 and the second prism 532 relative to the cross dichroic prism 54 in directions D3 to D6 within a plane perpendicular to the illumination optical axis Ax. Since the adjustment is performed, if the manufactured optical device 5 is incorporated in the projector 1, a clearer image without pixel shift of each liquid crystal panel 51 can be obtained.

  Further, as the liquid crystal panel 51, the exit-side polarizing element 53, and the cross dichroic prism 54 that are fixed to each other, materials having substantially the same linear expansion coefficient such as glass can be selected, so that the heat between the members 51, 53, and 54 can be selected. Expansion deformation can be accommodated in substantially the same level. Therefore, the thermal stress generated due to the difference in the linear expansion coefficient can be relieved, the mutual displacement of the liquid crystal panels 51 can be prevented, and the pixel displacement can be avoided.

  Further, in the liquid crystal panel 51, the first prism 531 is fixed to the drive substrate 511, and the incident side polarization element 52 is fixed to the counter substrate 512, so that dust adheres to the light incident side and the light output side. However, it is not necessary to attach dust-proof glass for shifting the dust from the focus position and preventing the dust from being displayed as a shadow in the projected image, and the configuration of the optical device 5 can be simplified and miniaturized.

  Further, since each incident side polarizing element 52, each liquid crystal panel 51, each exit side polarizing element 53, and the cross dichroic prism 54 are integrated in close contact with each other, for example, if the cross dichroic prism 54 is cooled, The entire optical device 5 can be easily cooled. For this reason, the cooling structure of the optical device 5 can also be simplified.

[Second Embodiment]
Next, 2nd Embodiment of this invention is described based on drawing.
In the following description, the same structure and the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.
FIG. 8 is an exploded perspective view schematically showing the configuration of the optical device 5 in the second embodiment.
This embodiment is different from the first embodiment only in the configuration of the exit-side polarizing element 53 as shown in FIG. Further, with the change in the configuration of the exit-side polarizing element 53, the manufacturing method of the optical device 5 is different from that of the first embodiment. Other configurations are the same as those in the first embodiment.

In the present embodiment, the exit-side polarizing element 53 includes a third prism 534 in addition to the first prism 531, the second prism 532, and the polarizing element body 533 described in the first embodiment, as shown in FIG. Prepare.
Here, unlike the first embodiment, the second prism 532 is disposed as shown below.
That is, in the second prism 532, the light exit side end surface 532A is orthogonal to the illumination optical axis Ax, the incident side inclined surface 532B is located on the light incident side, and the incident side inclined surface 532B and the light exit side end surface 532A Similarly to the first prism 531, the separation dimension along the illumination optical axis Ax is arranged so as to become smaller in the downward direction (first direction).

The third prism 534 is a triangular prism that is interposed between the prisms 531 and 532 and has a first opposing surface 534A parallel to the exit-side inclined surface 531B and a second opposing surface 534B parallel to the incident-side inclined surface 532B. It is configured. The third prism 534 has the same refractive index as the prisms 531 and 532.
Here, although the polarization element body 533 is not specifically shown, it is formed on the first facing surface 534A unlike the first embodiment.

Each of the exit-side polarizing elements 53 was held in an initial state of being in close contact with each other at the time of manufacturing the optical device 5 described later (in the present embodiment, in the state of being in close contact with each other so as to have a rectangular parallelepiped shape as a whole). At this time, according to the back focus position corresponding to each color light of the projection lens 4, similarly to the first embodiment, the light flux incident side end surface 531 </ b> A and the light beam emission side end surface 532 </ b> A are formed to have different separation dimensions. .
Regarding the optical path of the light beam emitted from the exit side polarization element 53, the first linearly polarized light L11 separated by the polarization element body 533 is introduced into the second prism 532 via the third prism 534. However, since it is only different from the first embodiment, the description is omitted.

Next, a method for manufacturing the optical device 5 in the second embodiment will be described.
FIG. 9 is a flowchart illustrating a method for manufacturing the optical device 5.
FIG. 10 is a diagram for explaining a manufacturing method of the optical device 5. Specifically, FIG. 10 is a diagram for explaining the focus adjustment process, and is a view of the optical device 5 seen from the side.
First, similarly to the first embodiment, the panel unit 6 is generated (step S1).
After step S1, the light exit side end surface 532A of the second prism 532 is fixed to the light entrance side end surface 54A of the cross dichroic prism 54 with an adhesive or the like (step S1A). Hereinafter, a unit in which the second prism 532 and the cross dichroic prism 54 are integrated will be described as the prism unit 7.

After step S1A, the prism unit 7 is installed at a predetermined position in a manufacturing apparatus (not shown) (step S2A).
After step S2A, a photocurable adhesive is applied to the incident side inclined surface 532B. Then, the third prism 534 is held by the focus adjustment jig 300 (FIG. 10) for adjusting the position of the liquid crystal panel 51 with respect to the cross dichroic prism 54, and the incident side on which the photocurable adhesive is applied. The second facing surface 534B is brought into close contact with the inclined surface 532B (step S3A).

After step S3A, a photocurable adhesive is applied to the surplus portion of the first facing surface 534A where the polarizing element body 533 is not formed. Then, the panel unit 6 is held by the alignment adjustment jig 400 (FIG. 10) for adjusting the position of the liquid crystal panel 51 with respect to the cross dichroic prism 54, and the first facing to which the photocurable adhesive is applied. The exit side inclined surface 531B is brought into close contact with the surface 534A (step S4A).
By the steps S2A to S4A described above, as shown in FIG. 10A, the first prism 531, the third prism 534, and the second prism 532 have a rectangular parallelepiped shape as a whole, and the liquid crystal panel 51, the exit side polarization The element 53 and the cross dichroic prism 54 are held in an initial state where they are in close contact with each other.
That is, steps S2A to S4A correspond to the optical device holding step according to the present invention.

After step S4A, the position adjustment of the liquid crystal panel 51 with respect to the cross dichroic prism 54 is performed as shown below with the photo-curing adhesive in an uncured state.
First, as in the first embodiment, a light beam for position adjustment is introduced into the liquid crystal panel 51 (step S5), and image light is confirmed via the liquid crystal panel 51, the exit side polarization element 53, and the cross dichroic prism 54. (Step S6).
In step S6, the third prism 534 is used as shown in FIGS. 10B and 10C using the focus adjustment jig 300 while confirming the projected image on the screen and the captured image such as a monitor. Are moved in the vertical directions D7 and D8, and the panel unit 6 is positioned at a position where the projected image and the captured image are in focus (step S7A: focus adjustment step).
Here, the alignment adjustment jig 400 regulates movement of the panel unit 6 in a plane orthogonal to the illumination optical axis Ax, and holds the panel unit 6 so as to be movable along the illumination optical axis Ax. That is, by moving the third prism 534 in the up and down directions D7 and D8, the panel unit 6 is placed on the first facing surface 534A by the surface tension of the photo-curing adhesive between the panel unit 6 and the third prism 534. It moves in the direction along the illumination optical axis Ax while maintaining the close contact state. Then, similarly to the focus adjustment step S7 described in the first embodiment, the separation dimension L (FIG. 10) between the light beam incident side end surface 531A and the light beam emission side end surface 532A is changed, and the liquid crystal panel 51 is changed to the projection lens. 4 is located at the back focus position.

After step S7A, while confirming the projected image and the captured image, the alignment adjustment jig 400 is used to move only the panel unit 6 in two directions (up and down direction in FIG. 10) in a plane orthogonal to the illumination optical axis Ax. And the pixel in the projected image or captured image is positioned at a predetermined position for matching the pixels of the liquid crystal panels 51 (step S8A: alignment adjustment step).
After step S8A, the photo-curing adhesive between the second prism 532 and the third prism 534 and between the third prism 534 and the first prism 531 is cured by irradiating ultraviolet rays or the like, and the cross dichroic prism 54 is applied to the cross dichroic prism 54. On the other hand, the liquid crystal panel 51 and the exit side polarization element 53 are fixed (step S9A: fixing step).
The optical device 5 is manufactured by performing the above steps on the three liquid crystal panels 51 and fixing the incident-side polarizing elements 52 to predetermined positions of the respective counter substrates 512 of the liquid crystal panels 51 with an adhesive or the like. Is done.

  According to the second embodiment described above, even when the third prism 534 is provided in addition to the first prism 531 and the second prism 532 as the configuration of the exit side polarization element 53, the prisms 531 and 532 are described above. By arranging as described above and configuring the third prism 534 in the shape described above, it is possible to enjoy the same effects as in the first embodiment.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In each of the embodiments described above, the manufacturing method of the optical device 5 is not limited to the flow of FIGS. 4 and 9, and the procedure may be changed as appropriate and another flow may be used.
For example, the liquid crystal panel 51 and the first prism 531 are fixed to generate the panel unit 6, but not limited to this, the liquid crystal panel 51 and the first prism 531 are in close contact with a photocurable adhesive, The members 51 and 531 are held by the adjustment jigs independent of each other. In the focus adjustment step S7, the members 51 and 53 are moved together using the adjustment jigs. In the alignment adjustment steps S8 and S8A, the liquid crystal panel 51 is moved with respect to the first prism 531 using one adjustment jig.

Further, for example, in the first embodiment, the panel unit 6 is moved together with the second prism 532 in the alignment adjustment step S8. However, as in the second embodiment, the prism unit 7 is generated in advance. The panel unit 6 may be moved with respect to the second prism 532.
Further, for example, in the second embodiment, the panel unit 6 is moved with respect to the third prism 534 in the alignment adjustment step S8A. However, similarly to the first embodiment, the cross dichroic prism 54 and the second prism 534 are moved. The prisms 532 may be brought into close contact with a photocurable adhesive, and the prisms 531, 532, and 534 may be moved together with respect to the cross dichroic prism 54.

Further, for example, in each of the above embodiments, the photo-curing adhesive is used. However, the present invention is not limited thereto, and a thermosetting adhesive may be used. Further, the focus adjustment steps S7 and S7A and the alignment adjustment steps S8 and S8A are performed in a state where the adhesive is uncured. However, after adjusting the position of the liquid crystal panel 51 without using an adhesive when adjusting the position of the liquid crystal panel 51 It may be fixed with an adhesive or the like.
Furthermore, for example, in the case where an image pickup device such as a CCD camera is used when checking image light in step S6, the following configuration may be adopted.
That is, a control device including a PC (Personal Computer) or the like is used. Then, the control device determines whether or not the captured image captured by the imaging device is in an in-focus state and whether or not the pixel in the captured image is located at a predetermined position by image processing. In addition, the control device drives and controls each of the adjustment jigs 100, 200, 300, and 400 so that the captured image is in a focused state and each pixel in the captured image is positioned at a predetermined position. 51 focus adjustment and alignment adjustment are performed.

In each of the embodiments described above, the polarizing element body 533 is formed on the incident-side inclined surface 532B and the first facing surface 534A, but is not limited thereto, and may be formed on the emission-side inclined surface 531B.
In each of the above-described embodiments, the optical device 51 is configured by integrating the optical components 51 to 54. However, the present invention is not limited to this, and at least the liquid crystal panel 51, the exit-side polarizing element 53, and the cross dichroic prism 54 are integrated. If it is the structure which was made, it does not matter as a structure where the incident side polarizing element 52 is not integrated.
In each of the above-described embodiments, when the optical device 5 is manufactured, the exit-side polarizing element 53 has a rectangular parallelepiped shape as a whole as an initial state for holding the members 51, 53, and 54. As long as the members 531 to 534 are in close contact with each other, a state where the members 531 to 534 are shifted from each other may be set as the initial state.

In the above embodiments, the first prism 531, the second prism 532, and the third prism 534 are not limited to the shapes described in the above embodiments, and other shapes may be employed. In addition, the first prism 531, the second prism 532, and the third prism 534 may have different refractive indexes.
For example, the shape of the end face 531C of the first prism 531 may be formed so that the second linearly polarized light L12 totally reflected by the light incident side end face 531A is incident orthogonally.
In each of the above-described embodiments, the emission-side inclined surface 531B is positioned on the light-beam emission side so that the second linearly polarized light L12 is emitted upward, and is on a plane (light-beam-incidence-side end surface 531A) orthogonal to the illumination optical axis Ax. However, the present invention is not limited to this, and as long as the liquid crystal panel 51 is avoided, the emission side inclined surface 531B may be inclined in any direction, up, down, left, or right.

In each of the above embodiments, the configuration of the polarizing element body 533 is not limited to the configuration described in each of the above embodiments, and any configuration may be used as long as it is a reflective polarizer.
For example, as the polarizing element body 533, a polymer-type layered polarization in which an organic material having refractive index anisotropy (birefringence) such as a polarization separation element formed of a dielectric multilayer film or a liquid crystal material is laminated in layers. A plate, an optical element that combines a λ / 4 phase difference plate and a circularly polarized light reflecting plate that separates unpolarized light into clockwise circularly polarized light and counterclockwise circularly polarized light, and reflected polarized light using Brewster's angle. You may employ | adopt the optical element isolate | separated into transmitted polarized light, or the hologram optical element using a hologram.
In each of the embodiments, only the example of the front projection type projector has been described. However, the present invention is also applicable to a rear type projector that includes a screen and performs projection from the back side of the screen.

  The present invention can easily adjust the focus of each light modulation element in an optical device in which a plurality of light modulation elements, a plurality of exit side polarization elements, and a color combining optical device are integrated. The present invention can be used in a method for manufacturing an optical device that constitutes a projector to be used.

FIG. 2 is a diagram schematically illustrating a schematic configuration of a projector according to the first embodiment. The disassembled perspective view which shows the structure of the optical apparatus in the said embodiment typically. The figure which shows typically the optical path of the light beam inject | emitted from the output side polarizing element in the said embodiment. 6 is a flowchart for explaining a method for manufacturing an optical device according to the embodiment. The figure for demonstrating the manufacturing method of the optical apparatus in the said embodiment. The figure for demonstrating the manufacturing method of the optical apparatus in the said embodiment. The figure for demonstrating the manufacturing method of the optical apparatus in the said embodiment. The disassembled perspective view which shows typically the structure of the optical apparatus in 2nd Embodiment. 6 is a flowchart for explaining a method for manufacturing an optical device according to the embodiment. The figure for demonstrating the manufacturing method of the optical apparatus in the said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 5 ... Optical apparatus, 51 ... Liquid crystal panel (light modulation element), 53 ... Output side polarizing element, 54 ... Cross dichroic prism (color synthesis optical apparatus), 531 ··· first prism, 531A ... luminous flux incident side end surface, 531B ... emission side inclined surface, 532 ... second prism, 532A ... luminous flux emission side end surface, 532B ... incident side inclined surface, 533: Polarizing element body, 534: Third prism, 534A: First opposing surface, 534B: Second opposing surface, S2 to S4, S2A to S4A ... Optical device holding step, S7 , S7A: Focus adjustment step, S9, S9A: Fixing step.

Claims (3)

A plurality of light modulation elements that modulate the plurality of color lights in accordance with image information for each color light to form image light, and a color synthesis optical device that combines the image lights formed by the plurality of light modulation elements; A method of manufacturing an optical device comprising a plurality of exit-side polarizing elements respectively disposed between the plurality of light modulation elements and the color combining optical device,
The exit side polarizing element is:
A first prism having a light beam incident side end surface that is in contact with the light modulation element and receives the image light, and an emission side inclined surface that is inclined with respect to the light beam incident side end surface;
A second prism having a light-emitting side end surface parallel to the light-incident-side end surface and contacting the color combining optical device; and an incident-side inclined surface that is inclined with respect to the light-emitting side end surface and parallel to the emission-side inclined surface; ,
Provided on the exit-side inclined surface or the incident-side inclined surface, the first linearly polarized light is transmitted through the first prism and introduced into the second prism, and the polarization direction is the first direction. A polarizing element body that reflects the second linearly polarized light orthogonal to the linearly polarized light toward the first prism;
The manufacturing method is
An optical device holding step for holding the light modulation element, the exit-side polarization element, and the color synthesis optical device in an initial state in close contact with each other;
A focus adjustment step of changing the relative position of each prism along the inclination direction of each inclined surface, and adjusting the position of the color light in the light modulation element in the optical axis direction;
A fixing step of fixing the light modulation element and the exit-side polarization element to the color synthesis optical device. A plurality of light modulation elements that modulate the plurality of color lights in accordance with image information for each color light to form image light, and a color synthesis optical device that combines the image lights formed by the plurality of light modulation elements; A method of manufacturing an optical device comprising a plurality of exit-side polarizing elements respectively disposed between the plurality of light modulation elements and the color combining optical device,
The exit side polarizing element is:
A light beam incident side end surface that is in contact with the light modulation element and receives the image light; and an emission side inclined surface that is inclined with respect to the light beam incident side end surface; and the light beam incident side end surface and the emission side inclined surface A first prism disposed such that a separation dimension of the color light in the optical axis direction is reduced along a first direction orthogonal to the optical axis;
A light beam emission side end surface parallel to the light beam incident side end surface and in contact with the color combining optical device; and an incident side inclined surface inclined with respect to the light beam emission side end surface, the light beam emission side end surface and the incident side inclination A second prism disposed so that a separation dimension in the optical axis direction with respect to a surface decreases along the first direction;
A third prism interposed between the prisms and having a first opposing surface parallel to the exit-side inclined surface and a second opposing surface parallel to the incident-side inclined surface;
The first linearly polarized light is transmitted through the first prism and is introduced into the third prism, and the direction of polarization is the first direction. A polarizing element body that reflects the second linearly polarized light orthogonal to the linearly polarized light toward the first prism;
The manufacturing method is
An optical device holding step for holding the light modulation element, the exit-side polarization element, and the color synthesis optical device in an initial state in close contact with each other;
A focus adjustment step of moving the third prism forward and backward along the first direction with respect to the first prism and the second prism, and adjusting a position of the light modulation element in the optical axis direction;
A fixing step of fixing the light modulation element and the exit-side polarization element to the color synthesis optical device. In the manufacturing method of Claim 1 or Claim 2,
The plurality of exit side polarization elements are:
In the initial state, the manufacturing method is characterized in that the separation dimension of the light beam incident side end surface and the light beam emission side end surface is different depending on the corresponding color light.

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