JP2009288262A - Polarization conversion element and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarization conversion element and an image display device in which the deterioration such as the peeling of a place where a retardation plate is fixed to a polarization panel is prevented even after a fixed period has elapsed. <P>SOLUTION: The polarization conversion element 5 includes a polarization panel 31 in which a first strip-shaped region part 31c including a polarization beam splitter 31a transmitting a first polarized light and reflecting a second polarized light crossing the first polarized light at a right angle and a second strip-shaped region part 31f including a reflection film 31d reflecting the second polarized light are arranged at prescribed intervals, the retardation plate 32 arranged in the light emitting side of one of the first strip-shaped region part 31c and the second strip-shaped region part 31f and converting the polarized direction of emitting light from the polarized light panel 31 and a joining agent 33 arranged only in a non-light transmission region in the light transmission effective functional region and the non-light transmission region positioned in the surround thereof in the polarization panel 31 and fixing the retardation plate 32 to the polarization panel 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polarization conversion element that aligns the polarization direction of light in one direction and an image display apparatus using the polarization conversion element.

  As one of image display devices using liquid crystal display elements, a liquid crystal projector device is known. A liquid crystal projector device modulates light emitted from a light source such as a high-pressure mercury lamp with a liquid crystal display element to form an optical image corresponding to a video signal, and enlarges and projects the optical image with a projection lens on a screen. It is configured to display. With such a configuration, the liquid crystal projector device is widely used as means for enlarging and projecting presentation materials such as conferences and lectures.

  In such a liquid crystal projector device, generally, the irradiation light from the light source includes an S-polarized component and a P-polarized component. On the other hand, the light necessary for the projection of the optical image using the liquid crystal display element is only the polarization component of either S-polarized light or P-polarized light. Therefore, the liquid crystal projector device is equipped with a polarization conversion element that aligns the polarization direction of light in one direction on the optical path between the light source and the liquid crystal display element, thereby efficiently using light energy. It is possible to do.

  As the polarization conversion element, for example, as shown in FIG. 8, a light shielding plate 52 for selectively transmitting light that has passed through the lens array 51, and a region in which a polarization beam splitter 53 a is formed along the light shielding plate 52. And a retardation plate (for example, a ½ wavelength) disposed only on one light emitting side of each region portion. Plate) 54) is known. In the polarization conversion element having such a configuration, the polarized light of a predetermined polarization component (for example, P polarization component) out of the light incident on the polarization panel 53 is transmitted through the polarization beam splitter 53a as it is, and polarized light orthogonal thereto. The polarized light of the component (for example, S polarization component) is reflected by the polarization beam splitter 53a. The polarized light of the polarization component (for example, S polarization component) reflected by the polarization beam splitter 53a is reflected in the emission direction by the reflection film 53b in the adjacent region. Then, either the light transmitted through the polarization beam splitter 53a or the light reflected by the reflection film 53b is converted into polarized light having orthogonal polarization components by the phase difference plate 54 (for example, the polarization beam splitter). The polarized light of the P-polarized component transmitted through 53a is converted into the polarized light of the S-polarized component). Therefore, the light emitted from the polarization conversion element is the light whose polarization direction is aligned in one direction (for example, all the polarized light of the S polarization component).

By the way, in the liquid crystal projector device, the light density tends to increase in order to meet the demands for downsizing the device and increasing the brightness. Therefore, an optical component constituting the liquid crystal projector device, particularly a polarization conversion element used for aligning the polarization state of light, is required to have excellent light resistance and heat resistance.
A polycarbonate film is usually used for the phase difference plate 54 that is one of the components of the polarization conversion element. However, the polycarbonate film is difficult in terms of heat resistance, light resistance, durability, and the like.
For this reason, it has been proposed that the phase difference plate 54 constituting the polarization conversion element is formed using quartz that is an inorganic material (see, for example, Patent Document 1).

JP 2003-302523 A

However, the polarization conversion element in which the phase difference plate 54 is made of quartz has a longer life than that using a polycarbonate film, but it has also been confirmed that deterioration occurs after a certain period of time. As a phenomenon of deterioration, the adhesive surface between the phase difference plate 54 and the polarizing panel 53 is peeled off by the influence of light, heat, or the like. More specifically, the retardation plate 54 and the polarizing panel 53 are bonded to each other using, for example, an ultraviolet curable adhesive. For example, the light from the illumination system is caused by the difference in thermal expansion coefficient. Peeling occurs in the vicinity of the center of the panel where the strength of the panel is stronger than that of the outer periphery of the panel, and this gradually spreads around the periphery.
Such deterioration in the polarization conversion element adversely affects the image quality displayed on the screen and should be avoided.

  Therefore, the present invention provides a polarization conversion element and an image display device that do not cause deterioration such as peeling off of a fixing portion of a retardation plate with respect to a polarizing panel even after a certain period of time has elapsed. Objective.

  The present invention is a polarization conversion element devised to achieve the above object, and a polarized beam that transmits first polarized light of a predetermined polarization component and reflects second polarized light of a polarization component orthogonal to the predetermined polarization component A first strip-shaped region portion on which a splitter is formed and a second strip-shaped region portion on which a reflective film that reflects the second polarized light reflected by the polarizing beam splitter is arranged in parallel at a predetermined interval. The polarizing panel is arranged on one of the light exit sides of the first strip-shaped region portion and the second strip-shaped region portion, and converts the polarization direction of the light emitted from the polarizing panel. Out of the retardation plate and the light transmission effective functional region in the polarizing panel and the non-light transmission region located around the retardation plate, the retardation plate is disposed only in the non-light transmission region, and the retardation plate is fixed to the polarization panel. With bonding agent to perform It is intended.

In the polarization conversion element having the above configuration, the phase difference plate is fixed to the polarizing panel by a bonding agent disposed only in the non-light transmission region. That is, in the light transmission effective functional region, the fixing with the bonding agent is not performed. Here, “fixing” means fixing so as not to move while staying at a certain place. Further, the “bonding agent” here is interposed between members for fixing, and specifically, an adhesive or a pressure-sensitive adhesive corresponds to this. The “light transmission effective function area” means an area that functions effectively for image display by transmitting light, and the “non-light transmission area” means the outer peripheral side of the light transmission effective function area. Is a region that does not function for image display and does not transmit light.
As described above, when the polarizing panel and the retardation plate are fixed only in the non-light transmission region, the bonding agent does not peel off in the light transmission effective functional region. In addition, unlike the case where the light transmission effective functional area is fixed, the bending that occurs in the polarizing panel or the phase difference plate does not restrict each other, so there is a difference in the amount of thermal expansion. Even if it exists, it comes to be able to be absorbed by the said bending, and the bad influence does not reach to the adhering location of the bonding agent in a non-light transmissive area.

According to the present invention, in the polarization conversion element that aligns the polarization direction of light in one direction, the polarizing panel is positioned in the light transmission effective function region, particularly in the vicinity of the central portion of the light transmission effective function region where the light intensity is the strongest. Since there is no bonding agent for fixing to the phase difference plate, the bonding agent does not peel off. That is, even after a certain period of time has passed, there is no possibility that deterioration such as peeling off of the fixing portion of the retardation film with respect to the polarizing panel will occur. Therefore, if image display is performed using the polarization conversion element, it is possible to maintain and ensure good image quality.
Moreover, in the present invention, since the bonding agent disposed only in the non-light-transmitting region fixes the polarizing panel and the retardation plate, the amount of the bonding agent used compared to the case where the entire surface of the retardation plate is applied. Therefore, it can be expected that the manufacturing cost can be reduced.

  Hereinafter, a polarization conversion element and an image display device according to the present invention will be described with reference to the drawings.

  First, a schematic configuration of an image display device according to the present invention will be described by taking a liquid crystal projector device as an example. As the liquid crystal projector apparatus, a so-called three-plate type apparatus having a liquid crystal panel corresponding to each of R (red) color, G (green) color, and B (blue) color is widely known.

FIG. 1 is a schematic diagram illustrating a schematic configuration example of a three-plate liquid crystal projector apparatus. The figure shows a schematic configuration example of a liquid crystal projector device using a transmissive liquid crystal panel.
As shown in the figure, in the liquid crystal projector device, the light emitted from the light source 1 is a filter 2 that cuts infrared rays or ultraviolet rays, a first fly-eye lens 3, a second fly-eye lens 4, a polarization conversion element 5, and a light collecting element. After passing through the lens 6, it is separated into RGB color component light by a dichroic mirror 7 that reflects only light in a specific wavelength band, and if necessary, a filter 8, a total reflection mirror 9, and a condenser lens 10 that absorb ultraviolet rays. The light is incident on the liquid crystal panels 13R, 13G, and 13B provided corresponding to the RGB colors while using the relay lens 11 and the like. Each liquid crystal panel 13R, 13G, 13B is provided with an incident-side polarizing plate 12, an optical compensator pair 14 and an output-side polarizing plate 15, and each color component transmitted through the incident-side polarizing plate 12 is attached thereto. Light enters each liquid crystal panel 13R, 13G, 13B, and each color component light modulated by each liquid crystal panel 13R, 13G, 13B passes through the optical compensator pair 14 and the output side polarizing plate 15. Yes. Then, after light modulation according to the video signal is performed in each of the liquid crystal panels 13R, 13G, and 13B, each color component light that has been light-modulated passes through the half-wave film 16 and is dichroic prism 17 as necessary. The images are combined and enlarged and projected by the projection lens 18. In this way, the liquid crystal projector device displays a color image on the screen.

FIG. 2 is a schematic diagram illustrating another schematic configuration example of a three-plate liquid crystal projector apparatus. The figure shows a schematic configuration example of a liquid crystal projector device using a reflective liquid crystal panel.
Also in the liquid crystal projector device of the example, as in the case of the liquid crystal projector device using the transmissive liquid crystal panel (see FIG. 1), the light emitted from the light source 1 is filtered, the first fly-eye lens 3, the first After passing through the 2 fly-eye lens 4, the polarization conversion element 5, and the condenser lens 6, it is separated into RGB color component lights by the dichroic mirror 7. Then, each color component light is incident on the liquid crystal panels 20R, 20G, and 20B provided corresponding to each color of RGB while using the total reflection mirror 9 and the polarization beam splitter (PBS) 19 as necessary. . Thereafter, the liquid crystal panels 20R, 20G, and 20B perform light modulation in accordance with the video signal, and the light-modulated color component lights are synthesized by the dichroic prism 27 and enlarged and projected by the projection lens 18. In this way, the liquid crystal projector device displays a color image on the screen.

  Next, the polarization conversion element 5 used in the liquid crystal projector apparatus having the above configuration will be described in detail.

First, a basic configuration of the polarization conversion element 5 will be described.
FIG. 3 is a side sectional view showing a schematic configuration example of the polarization conversion element according to the present invention.
As shown in the figure, the polarization conversion element 5 includes a polarizing panel 31, a phase difference plate 32, a bonding agent 33, and an antireflection film 34.

The polarizing panel 31 includes a first strip-shaped region portion 31c in which the polarizing beam splitter 31a is sandwiched between the transparent members 31b, and a second strip-shaped region portion 31f in which the reflective film 31d is sandwiched between the transparent members 31e. Are arranged in parallel at a predetermined interval.
The polarization beam splitter 31a in the first strip-shaped region portion 31c is disposed so as to form an angle of approximately 45 ° with respect to the optical axis direction. Then, the first polarized light of a predetermined polarization component (for example, P polarization component) is transmitted as it is, but the second polarized light of a polarization component (for example, S polarization component) orthogonal to the predetermined polarization component is reflected. It has become.
On the other hand, the reflective film 31d in the second strip-shaped region portion 31f is arranged so as to form an angle of about 45 ° with respect to the optical axis direction, like the polarizing beam splitter 31a. The second polarized light reflected by the polarization beam splitter 31a is reflected.
As the transparent members 31b and 31e, for example, a glass material may be used.
As shown in the figure, in the polarizing panel 31, the first and second strip-shaped region portions 31c and 31f are arranged so that the tilt directions of the polarizing beam splitter 31a and the reflective film 31d are symmetrical with respect to the center portion of the panel. Each of these is assumed to be disposed.

The phase difference plate 32 is formed in a strip-like flat plate shape using quartz, which is an inorganic material, and is disposed on the light emission side of one of the first and second strip-shaped region portions 31c and 31f. Thus, the polarization direction of the light emitted from the polarizing panel 31 is converted. Specifically, as shown in the figure, the first strip-shaped region portion 31c is transmitted through the first strip-shaped region portion 31c by being arranged on the light emitting side of the first strip-shaped region portion 31c and functioning as a half-wave plate. The first polarized light of the polarized component (for example, P-polarized component) is converted into the second polarized light of the polarized component (for example, S-polarized component) orthogonal thereto.
The phase difference plate 32 may be composed of a laminated structure of a plurality of quartz plates.

The bonding agent 33 fixes the polarizing panel 31 and the phase difference plate 32. However, the bonding agent 33 is configured to fix the retardation plate 32 to the polarizing panel 31 only at locations where details will be described later.
Here, “fixing” means fixing so as not to move while staying at a certain place. Further, the “bonding agent” here is interposed between members for fixing, and specifically, an adhesive or a pressure-sensitive adhesive corresponds to this.
The type of the bonding agent 33 is not particularly limited, and various adhesives or pressure-sensitive adhesives can be used. However, the bonding agent 33 is soft and excellent in impact resistance, and is also resistant to heat. It is preferable to use an excellent one.

  The antireflection film 34 is made of, for example, an AR (anti-reflection) coating by vapor deposition, sputtering, or the like. In order to prevent surface reflection, the light exit surface of the polarization panel 31 and the light entrance surface and the light exit of the retardation plate 32 It is given to each of the faces.

  The polarization conversion element 5 may be provided with a light shielding plate (not shown) for selectively transmitting light on the light incident surface side of the polarization panel 31 as necessary.

In the polarization conversion element 5 having such a configuration, of the light incident on the polarization panel 31, the polarization light of the P polarization component which is a predetermined polarization component passes through the polarization beam splitter 31a as it is, and is a polarization component orthogonal to this. Polarized light of a certain S-polarized component is reflected by the polarization beam splitter 31a. The polarized light of the S-polarized component reflected by the polarization beam splitter 31a is reflected in the emission direction by the reflective film 31d in the adjacent region. The light transmitted through the polarization beam splitter 31a is converted by the phase difference plate 32 into P-polarized component polarized light into S-polarized component polarized light. Therefore, all the light emitted from the polarization conversion element 5 becomes the polarization light of the S polarization component, and the polarization direction is aligned in one direction.
Here, the case where all the light is aligned with the polarized light of the S-polarized component is taken as an example, but it is of course possible to configure it so that all the light is aligned with the polarized light of the P-polarized component.

Next, the planar configuration of the polarization conversion element 5 will be described.
FIG. 4 is a plan view showing an outline of a basic planar configuration example of the polarization conversion element.
As shown in the figure, a light transmission effective function area 35 and a non-light transmission area 36 are formed on the panel surface of the polarization panel 31 in the polarization conversion element 5.

  The light transmission effective function area 35 is an area that functions effectively for image display when light is transmitted. Specifically, a rectangular area including a central vicinity area on the panel surface of the polarizing panel 31 corresponds to this. To do.

  Further, the non-light transmission region 36 is a region arranged so as to surround the outer peripheral side of the light transmission effective functional region 35 and is a region that does not function for image display and does not transmit light. Using this non-light transmission region 36, the polarization conversion element 5 is supported and fixed.

  Then, on the panel surface of the polarizing panel 31, either one of the first and second strip-shaped region portions 31c and 31f, specifically, the first strip-shaped region portion in which the polarization beam splitter 31a is disposed. A strip-shaped retardation plate 32 is arranged so as to correspond to each of 31c. The phase difference plate 32 is formed in a planar shape so that both end edges in the longitudinal direction of the strip shape protrude from the light transmission effective function region 35 and are positioned in the non-light transmission region 36.

  By the way, there are problems as described below regarding the fixing of the retardation film 32 on the panel surface of the polarizing panel 31.

It is conceivable that the retardation plate 32 is fixed on the panel surface of the polarizing panel 31 by adhering the entire surface using, for example, an ultraviolet curable adhesive.
However, when the entire surface is bonded with the ultraviolet curable adhesive, the polarizing panel 31 and the phase difference plate 32 are obtained when the ventilation duct in the liquid crystal projector device is closed and aging is performed in a state where cooling to the polarization conversion element 5 is intentionally stopped. It was found that peeling of the bonded portion occurred between the two.
FIG. 5 is an explanatory diagram showing a specific example of the occurrence of peeling on the panel surface and the progress of the peeling.
As shown in FIG. 5A, the polarizing panel 31 and the phase difference plate 32 start to peel off on the upper side of the portion near the center of the light transmission effective functional region 35 (see A part in the figure). This is because the light incident on the light transmission effective function region 35 has a light intensity profile as shown in FIG. It is thought to be higher. When peeling occurs in the vicinity of the center, the peeling progresses with time, and gradually spreads to the outside as shown in FIG.
On the other hand, the phase difference plate 32 itself does not peel off between the crystal plates even when, for example, a plurality of crystal plates are bonded together. Further, in the polarizing panel 31, peeling between the transparent members 31b and 31e does not occur.
Therefore, it is estimated that the cause of peeling between the polarizing panel 31 and the phase difference plate 32 is due to the difference in thermal expansion coefficient between the respective forming members. For example, the thermal expansion coefficient of white plate glass, which is an example of a material for forming the transparent members 31b and 31e in the polarizing panel 31, is 96 × 10 ⁻⁷ / ° C., which is a typical product of B270. On the other hand, the coefficient of thermal expansion of quartz, which is a material for forming the retardation film 32, is 79.9 × 10 ⁻⁷ / ° C. (parallel to the axis), 133.7 × 10 ⁻⁷ / ° C. (perpendicular to the axis). It is. That is, a difference in thermal expansion occurs due to such a difference in thermal expansion coefficient at a high temperature in the light transmission effective functional area 35, so that the polarization panel 31 and the retardation film 32 are thereby separated. It is thought that peeling occurs. In addition, the light intensity is the strongest in the vicinity of the center, but the warmed air rises. As a result, the temperature is highest in the portion slightly above the center, and at that point the first It is thought that peeling occurs. In particular, for the portion near the center in the light transmission effective functional region 35, the polarizing panel 31 is configured symmetrically, and the first strip-shaped region portions 31c are adjacent to each other. Since the plates 32 are arranged adjacent to each other, it is considered that the phase difference plates 32 are pressed against each other, so that peeling is more likely to occur.

In order to solve such a peeling problem, it is conceivable to change the type of adhesive. Specifically, as an alternative to a general UV curable adhesive, a) an acrylic adhesive with increased transmittance on the short wavelength side, and b) an acrylic adhesive at 200 ° C. in a heat resistance test. It is conceivable to use any one of those that can withstand up to, and c) silicon-based adhesives that have a heat resistant temperature of 200 ° C. or higher. The adhesive (a) has recently been used for Blu-ray Disc applications and has been improved so as to improve the transmittance on the short wavelength side as compared with general acrylic adhesives. This is because the short wavelength light has higher energy than the long wavelength light, and the deterioration proceeds more when it is absorbed. Therefore, the light is used for the purpose of increasing the transmittance and suppressing the energy absorption in the adhesive. . In addition, the adhesives b) and c) are expected to be thermally effective since they are excellent in heat resistance.
However, for example, even when the adhesive (a) is used in place of the ultraviolet curable adhesive, if the aging is performed for a certain period, the upper part of the light transmission effective functional region 35 near the center is used. It was confirmed that deterioration (peeling) occurred. When the adhesive of b) is used, the shrinkage at the time of curing is larger than that of the adhesive of b), and the hardness of the adhesive itself is high, and as a result, it deteriorates faster than the adhesive of b) Was confirmed to occur. In addition, because the adhesive of c) is silicon-based, it has better heat resistance than acrylic-based adhesives, but it is a thermosetting two-component type compared to the acrylic photo-curing type. Handling becomes difficult and time-consuming. Furthermore, since the viscosity is high, it is difficult to remove bubbles in the adhesive, resulting in poor production yields, and the price of the adhesive itself is higher than that of acrylic, resulting in an increase in product cost. There is a risk of it.

In addition, as described above, one of the factors that cause peeling easily is that the two retardation plates 32 are arranged adjacent to each other and press each other. Therefore, in order to suppress the occurrence of peeling, it is conceivable to arrange these so that the phase difference plates 32 are not pressed against each other.
FIG. 6 is an explanatory diagram illustrating a specific example in the case where a gap is provided between adjacent retardation plates.
As shown in FIG. 6A, a gap of, for example, about 0.1 to 0.3 mm is provided between the adjacent retardation plates 32 in the vicinity of the center in the light transmission effective functional region 35 (in the drawing). (See section B.) If the respective retardation plates 32 are arranged and bonded over the entire surface, even if each of the retardation plates 32 expands due to heat, it can be avoided that they are pressed against each other. .
However, even if a gap is secured between the phase difference plates 32, the time until the first peeling occurs can be extended as compared with the case where there is no gap, but when aging is performed for a certain period, FIG. As shown in (b), it was confirmed that degradation (peeling) also occurred.
Moreover, since the polarization direction of the emitted light is not aligned in one direction at the gap portion, the energy of the emitted light is reduced by that amount, and the brightness becomes darker by about 3%. Therefore, it cannot be said that it is preferable for application to a liquid crystal projector device that emphasizes brightness.

  In view of these matters, the polarization conversion element 5 described as an example in the present embodiment has a problem in fixing the polarizing panel 31 and the phase difference plate 32, that is, a problem of deterioration with time (peeling). In order to solve this problem, a characteristic plane configuration is provided as described below.

FIG. 7 is a plan view showing an outline of a characteristic planar configuration example of the polarization conversion element according to the present invention.
As illustrated, on the panel surface of the polarization panel 31 in the polarization conversion element 5, the retardation plate 32 is fixed to the polarization panel 31 only in the non-light transmission region 36. That is, the bonding agent 33 for fixing the polarizing panel 31 and the retardation plate 32 is disposed only in the non-light transmission region 36 and is not disposed in the light transmission effective function region 35 at all.

  In the polarization conversion element 5 having the planar configuration as described above, the phase difference plate 32 is fixed to the polarization panel 31 by the bonding agent 33 disposed only in the non-light transmission region 36. Therefore, for example, even after aging for a certain period, the bonding agent 33 does not peel off in the light transmission effective functional region 35. This is because the bonding with the bonding agent 33 is not performed in the light transmission effective function region 35. In addition, since the bending that occurs in the polarizing panel 31 or the retardation plate 32 does not regulate each other as in the case where the light transmission effective function area 35 is fixed, the respective thermal expansion amounts Even if there is a difference, it becomes possible to be absorbed by the bending, and the adverse effect does not reach the fixing portion of the bonding agent 33 in the non-light transmission region 36.

That is, according to the polarization conversion element 5 in the present embodiment, the polarizing panel 31 and the light transmission effective function region 35 are provided in the light transmission effective function region 35, particularly in the vicinity of the center of the light transmission effective function region 35 and its peripheral region. Since there is no bonding agent 33 that adheres to the phase difference plate 32, the bonding agent 33 does not peel off. That is, even after a certain period of time has elapsed, there is no possibility that deterioration such as peeling off of the fixing portion of the retardation plate 32 with respect to the polarizing panel 31 will occur. Therefore, if image display is performed using the polarization conversion element 5, it is possible to maintain and ensure good image quality.
In addition, in the polarization conversion element 5 according to the present embodiment, the bonding agent 33 disposed only in the non-light transmission region 36 fixes the polarizing panel 31 and the retardation plate 32, so that it is applied to the entire surface of the retardation plate 32. Compared with the case where it does, the usage-amount of the said bonding agent 33 may be small, and it can also be anticipated that a manufacturing cost can be aimed at by this.

In the polarization conversion element 5 according to the present embodiment, the bonding agent 33 is disposed only in the non-light transmission region 36 and does not exist in the light transmission effective function region 35. Therefore, an air layer is interposed between the polarizing panel 31 and the phase difference plate 32.
Therefore, in the polarization conversion element 5 according to this embodiment, the antireflection film 34 is coated on each of the light emitting surface of the polarizing panel 31 and the light incident surface and the light emitting surface of the phase difference plate 32. In other words, while avoiding the occurrence of deterioration such as peeling of the fixed portion, the reflection of light at the interface between the polarizing panel 31 and the phase difference plate 32 is prevented by using the antireflection film 34, and the light at the interface is prevented. Therefore, the light from the light source 1 can be efficiently transmitted. Therefore, the present invention is very suitable when applied to a liquid crystal projector device that emphasizes brightness.

Further, in the polarization conversion element 5 according to the present embodiment, the two phase difference plates 32 are disposed adjacent to each other in the vicinity of the central portion of the light transmission effective function region 35. Since the bonding agent 33 does not exist, it is suppressed that the phase difference plates 32 are pressed against each other. This is because, even if stress is generated due to thermal expansion in the two phase difference plates 32 that are in contact with each other, the stress is absorbed by the degree of freedom in the phase difference plate 32 itself, that is, the bending that occurs in the phase difference plate 32. .
Therefore, even if the polarizing panel 31 is configured symmetrically, and the first strip-shaped region portions 31c are adjacent to each other in the vicinity of the center in the light transmission effective functional region 35, the two corresponding to these are provided. There is no need to provide a gap between the phase difference plates 32. That is, since the energy of the emitted light (brightness reduction) is not caused by the gap, it is very suitable to be applied to the polarizing panel 31 that is configured symmetrically.

  In addition, although this embodiment demonstrated the suitable Example of this invention, this invention is not limited to the content.

  For example, in the present embodiment, the case where reliable fixing is realized with a simple configuration by fixing the polarizing panel 31 and the phase difference plate 32 using the bonding agent 33 has been described as an example. As long as only the light transmission region 36 is used, the polarizing panel 31 and the retardation plate 32 may be fixed using other fixing means. As other fixing means, for example, one using a fastener such as a screw or a clip can be cited.

  In this embodiment, the case where the polarizing panel 31 and the phase difference plate 32 are coated with the antireflection film 34 is taken as an example. However, if the decrease in the light use efficiency can be allowed, the antireflection film 34 is essential. It is not a configuration of.

  Furthermore, in the present embodiment, the polarizing panel 31 is configured to be bilaterally symmetric and the two retardation plates 32 are adjacent to each other in the vicinity of the center in the light transmission effective functional region 35. In the case of a configuration that is not symmetrical, that is, the configuration in which the polarizing beam splitter 31a and the reflective film 31d in the polarizing panel 31 are all inclined in the same direction, the present invention can be applied in exactly the same manner.

  Furthermore, in the present embodiment, the liquid crystal projector device has been described as an example of the image display device. However, any other image may be used as long as the image display device includes a polarization conversion element that aligns the polarization direction of light in one direction. The present invention can be applied to the display device in exactly the same manner.

  Thus, the present invention can be modified as appropriate without departing from the scope of the invention.

It is a schematic diagram showing a schematic configuration example of a three-plate liquid crystal projector device. It is a schematic diagram which shows the other schematic structural example of a three-plate liquid crystal projector device. It is a sectional side view which shows the schematic structural example of the polarization conversion element which concerns on this invention. It is a top view which shows the outline | summary of the basic planar structural example of a polarization converting element. It is explanatory drawing which shows the specific example of generation | occurrence | production of the peeling on the panel surface of a polarization conversion element, and the mode of the progress. It is explanatory drawing which shows the specific example at the time of providing and providing a clearance gap between the phase difference plates adjacent on the panel surface of a polarization converting element. It is a top view which shows the outline | summary of the example of a characteristic plane structure of the polarization conversion element concerning this invention. It is a sectional side view which shows the example of schematic structure of the conventional polarization conversion element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source, 5 ... Change conversion element, 13B, 13G, 13R, 20B, 20G, 20R ... Liquid crystal panel, 31 ... Polarizing panel, 31a ... Polarizing beam splitter, 31c ... 1st strip-shaped area | region part, 31d ... Reflective film , 31f: second strip-shaped region portion, 32: retardation plate, 33: bonding agent, 34: antireflection film, 35: light transmission effective functional region, 36: non-light transmission region

Claims (5)

A first strip-shaped region portion formed with a polarizing beam splitter that transmits the first polarized light of a predetermined polarization component and reflects the second polarized light of a polarization component orthogonal to the predetermined polarization component, and is reflected by the polarization beam splitter A polarizing panel in which a second strip-shaped region portion on which a reflective film that reflects the second polarized light is formed is arranged in parallel at a predetermined interval;
A phase difference plate that is arranged on one of the light exit sides of the first strip-shaped region portion and the second strip-shaped region portion and converts the polarization direction of the light emitted from the polarizing panel;
A bonding agent that is disposed only in the non-light transmissive region among the light transmissive effective functional region in the polarizing panel and the non-light transmissive region positioned around the functional region, and that bonds the retardation plate to the polarizing panel; A polarization conversion element provided. The polarization conversion element according to claim 1, further comprising: an antireflection film coated on each of a light emitting surface of the polarizing panel and a light incident surface and a light emitting surface of the retardation plate. The strip-shaped region portion of the polarizing panel is disposed so that the two retardation plates are arranged adjacent to each other in the vicinity of the central portion of the light transmission effective functional region. Polarization conversion element. A first strip-shaped region portion formed with a polarizing beam splitter that transmits the first polarized light of a predetermined polarization component and reflects the second polarized light of a polarization component orthogonal to the predetermined polarization component, and is reflected by the polarization beam splitter A polarizing panel in which a second strip-shaped region portion formed with a reflective film that reflects the second polarized light is arranged in parallel at a predetermined interval;
A phase difference plate that is arranged on one of the light exit sides of the first strip-shaped region portion and the second strip-shaped region portion and converts the polarization direction of the light emitted from the polarizing panel;
A fixing means that is disposed only in the non-light transmission region among the light transmission effective functional region in the polarization panel and the non-light transmission region located in the periphery thereof, and fixes the retardation plate to the polarization panel; A polarization conversion element provided. A light source that emits light;
A polarization conversion element that aligns the polarization direction of the irradiation light from the light source in one direction;
A liquid crystal display element that selectively transmits or reflects light emitted from the polarization conversion element to form an optical image;
The polarization conversion element is:
A first strip-shaped region portion formed with a polarization beam splitter that transmits first polarized light having a predetermined polarization component in the irradiation light and reflects second polarized light having a polarization component orthogonal to the predetermined polarization component; A polarizing panel in which a second strip-shaped region portion formed with a reflective film that reflects the second polarized light reflected by the beam splitter is arranged in parallel at a predetermined interval;
A phase difference plate that is arranged on one of the light exit sides of the first strip-shaped region portion and the second strip-shaped region portion and converts the polarization direction of the light emitted from the polarizing panel;
A bonding agent that is disposed only in the non-light transmissive region among the light transmissive effective functional region in the polarizing panel and the non-light transmissive region positioned around the functional region, and that bonds the retardation plate to the polarizing panel; An image display device provided.

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