JP2016118659A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device that can avoid the occurrence of trouble in curing an adhesive and simply and stably couple a prism and a light valve.SOLUTION: There is provided an image display device comprising a light modulation element, a prism that is provided on an emission side of the light modulation element, a holding member that holds the prism, and a coupling member that couples the holding member and the light modulation element, where one member of the holding member and the coupling member has a projection on its outside, and the one member is held inside the other member of the holding member and the coupling member through the projection.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device, and is particularly suitable for a projector.

  In recent years, a projector as an image display device has been improved in image quality. In particular, as PCs (personal computers) have higher image quality due to the influence of 4K televisions and the like, high-definition image quality is also required for projectors. On the other hand, since the size of the device is required as it is or downsizing, there is a tendency that a liquid crystal panel (light valve) having a current pixel size and a small pixel pitch is adopted. In the case of a projector having R, G, and B liquid crystal panels, the allowable amount of mutual positional deviation (relative positional deviation) is small, and very high accuracy is required for installation (fixation) of the light valve. .

  Conventionally, in order to bond and fix a light valve to a prism as an optical element with high positional accuracy, a coupling member (spacer) that fills the gap between the light valve and the prism is used to reduce the thickness of the adhesive layer as much as possible. (Patent Document 1). If the adhesive layer is thick, there is a high possibility that the strain at the time of curing of the adhesive will be released and move when exposed to high temperature or low temperature environment, but if the adhesive layer is thin, there is less distortion and misregistration may occur. Becomes lower.

JP 2013-54143 A

  Here, in the above-described prior art, it is not disclosed how to combine the prism and the light valve, and the holding structure of the coupling member (spacer) is not shown in the embodiment. It is thought that it is held with a jig or the like until it is bonded, and pressed together.

  However, when pressing with a jig, the jig must be configured in a small space between the prism and the panel (light valve), which is very difficult. In addition, when the bonding member is bonded and fixed using a UV adhesive (ultraviolet curable adhesive), the jig has a high possibility of inhibiting the UV light, and there is a high possibility of causing an obstacle to the curing of the adhesive. And when the obstacle to adhesive hardening arises, reliability and precision, such as a hardening defect and shift | offset | difference, may deteriorate.

  Moreover, when using a jig | tool, there exists a problem that the change between a press state and the state by which a press is released is large.

  An object of the present invention is to provide an image display device that can avoid the obstacle to the curing of the adhesive and can easily and stably combine the prism and the light valve.

  In order to achieve the above object, an image display device according to the present invention includes a light modulation element, a prism provided on an emission side of the light modulation element, a holding member that holds the prism, the holding member, and the light modulation. A coupling member that couples elements, and one of the holding member and the coupling member has a convex portion on the outside, and the one member is connected to the holding member and the coupling via the convex portion. It is characterized by being held inside the other member among the members.

  According to the present invention, it is possible to avoid the obstacle to the curing of the adhesive and to easily and stably combine the prism and the light valve.

It is a figure which shows the unit for image display apparatuses (prism panel unit) used for the image display apparatus which concerns on embodiment of this invention. It is a separation figure of a prism unit and a panel concerning an embodiment of the present invention. It is a prism panel unit exploded view concerning an embodiment of the present invention. It is the upper side figure and side view of a prism unit which concern on embodiment of this invention. It is a separation figure of a prism and a spacer concerning an embodiment of the present invention. It is a mounting process diagram of the prism and the spacer according to the embodiment of the present invention. 1 is a schematic optical configuration diagram of a projector as an image display apparatus according to an embodiment of the present invention.

<< First Embodiment >>
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Image display device)
FIG. 7 is a schematic optical configuration diagram of a projector as an image display apparatus according to an embodiment of the present invention. The light source unit 5 is a high-intensity light source such as an ultra-high pressure mercury lamp, and includes an arc tube that emits white light in a continuous spectrum, and a reflector that condenses the light in a predetermined direction. Irradiate toward 6. The illumination optical system 6 has a glass member such as a cylinder array, and by its optical action, a rectangular uniform illumination area in which rectangular images are superimposed on a plurality of light beams is formed, and the next stage color separation The optical unit 1 that is a combining optical system is illuminated.

  The optical unit 1 includes a dichroic mirror 1001 that reflects light in the blue (B) and red (R) wavelength regions and transmits light in the green (G) wavelength region. For light in the green (G) wavelength region, there is a half-wave plate 1002, a G-use incident side polarizing plate 1003 with a polarizing element attached to a transparent substrate that transmits only S-polarized light, and a polarization separation surface. A first polarization beam splitter 13G that transmits P-polarized light and reflects S-polarized light is provided.

  The S-polarized light reflected by the first polarizing beam splitter 13G serving as a prism that branches the optical path is converted to circularly polarized light via the green quarter-wave plate 12G, and is placed on the heat sink 112G. Head to light valve 111G. The quarter-wave plate 12G is provided in the optical path between the first polarizing beam splitter 13G and the green light valve 111G.

  The light reflected by the green light valve 111G is converted to P-polarized light through the green quarter-wave plate 12G. Then, the light passes through the first polarizing beam splitter 13G and the G exit-side polarizing plate 1010G that transmits only the P-polarized light, and travels toward the dichroic prism 1011 that transmits the RB light and reflects the G light.

  For R and B light reflected by the dichroic mirror 1001, an RB incident side polarizing plate 1006 and a color selective phase difference plate 1007 that transmit only P-polarized light and have a polarizing element attached to a transparent substrate are provided. It has been. The color-selective retardation plate 1007 has a function of converting the polarization direction of the R light by 90 degrees and not converting the polarization direction of the B light, so that light in the red (R) wavelength region is converted to S-polarized light. , Light in the blue (B) wavelength region passes through with P polarization. A trimming filter 1008 for returning orange light to the lamp is provided in the optical path that has passed through the color selective phase difference plate 1007 in order to increase the color purity of R.

  The second polarization beam splitter 13BR as a prism that transmits the P-polarized light, reflects the S-polarized light, and branches or combines the optical path reflects the S-polarized R light while the P-polarized B light. Is transparent. The R light reflected by the second polarizing beam splitter 13BR is circularly polarized through the red quarter-wave plate 12R and travels toward the red light valve 111R placed on the heat sink 112R. The light reflected by the red light valve 111R is converted to P-polarized light via the red quarter-wave plate 12R.

  Then, the light passes through the second polarizing beam splitter 13BR, the B output side polarizing plate (polarizing element) 1010B that rectifies only the S-polarized light of B, and the dichroic prism 1011 and enters the projection lens 7 as the projection optical system.

  On the other hand, the B light transmitted through the second polarizing beam splitter 13BR is circularly polarized through the blue quarter-wave plate 12B, and travels toward the blue light valve 111B placed on the heat sink 112B. . The light reflected by the blue light valve 111B is converted to P-polarized light through the blue quarter-wave plate 12B. Then, the light is reflected by the second polarizing beam splitter 13BR, passes through the B-use exit side polarizing plate (polarizing element) 1010B that rectifies only the S-polarized light of B, and passes through the dichroic prism 1011 and enters the projection lens 7 as the projection optical system. Incident.

  The red light valve 111R, the green light valve 111G, and the blue light valve 111B, which are reflective liquid crystal display elements, reflect incident light and modulate the image. Then, by using the above-described color separation / synthesis optical system, the images on the light valves 111R, 111G, and 111B are projected as color images onto the projection surface (screen surface) by the projection lens 7.

(Image display unit)
FIG. 1 is a diagram showing an image display device unit (prism / panel unit) used in an image display device according to an embodiment of the present invention. Reference numeral 1 denotes a prism (corresponding to the polarization beam splitters 13BR and 13G in FIG. 7), and 2 denotes a holding plate as a holding member that is bonded and fixed to the prism. Reference numeral 3 denotes a liquid crystal panel unit (having a reflective liquid crystal panel as a light modulation element), which has an aluminum heat sink on the back surface. Reference numeral 4 denotes a coupling member (spacer) made of an acrylic material as a translucent member so as to be bonded to the panel unit and the holding plate by a UV adhesive (ultraviolet curable adhesive). Reference numeral 5 denotes a spring, which is a member for pressing the spacer 4 toward the liquid crystal panel unit 3.

  Here, as shown in FIG. 3, two sets of the holding plate 2, the spacer 4, and the spring 5 are provided in the vertical direction.

  Assembly adjustment of the prism / panel unit according to the present embodiment will be described in detail with reference to FIGS. FIG. 2 shows a state in which the liquid crystal panel unit 3 is separated from the prism panel unit of FIG. This shows a state in which the liquid crystal panel unit 3 is fixed to the prism 1 from now on. The prism 1 is fixed to another member (not shown) and its position is determined. In order to fix the liquid crystal panel unit 3 to the prism 1 with high accuracy, the liquid crystal panel unit 3 is held by a robot arm or the like (not shown).

  The state shown in FIG. 3 is a state in which the prism 1 and the holding plate 2 are bonded and fixed (the state in which the prism 1 is held by the holding plate 2), but the other members are separated. . As will be described below, in the present embodiment, when changing from the state of FIG. 3 to the state of FIG.

  As shown in FIG. 2, in order to hold (hold) the spacer 4 on the holding plate 2, the spacer 4 is put inside the holding plate 2 (so-called nested structure). That is, in FIG. 3, the shaft portion 4 </ b> D of the spacer 4 enters the elongated hole portion 2 </ b> D of the holding plate 2 (directly or indirectly inserted), and the convex portion 4 </ b> C provided outside the spacer 4 becomes the concave portion 2 </ b> C of the holding plate 2. It is held by being caught (inserted). The spacer 4 has a slight degree of freedom in the optical axis direction (z direction), but sandwiches the spring 5 between the shaft portion 4D and the long hole portion 2D (the shaft portion 4D is indirectly inserted into the long hole portion 2D). In other words, the liquid crystal panel unit 3 is shifted toward the liquid crystal panel unit 3 in the optical axis direction (z direction).

  The convex portion 4C and the shaft portion 4D are fitted (inserted) into the concave portion 2c and the elongated hole portion 2D, respectively, so that the five-axis direction is regulated and the remaining optical axis direction is regulated by the spring 5. The restriction in the five-axis direction is that the holding plate 2 has a concave portion 2C on one end side and the other end side, and has a long hole portion 2D into which the shaft portion 4D of the spacer 4 is inserted in the center portion. However, this is possible because two sets of these are provided in the vertical direction (four each in total).

  Here, in order to fix the liquid crystal panel 3 with high accuracy, the spacer 4 needs a certain degree of freedom. The following explains how this degree of freedom is realized.

  The convex part 4C of the spacer 4 can move freely in the optical axis direction (z direction) within the groove of the concave part 2C. This is both one end side and the other end side in the short side direction (x direction) of the liquid crystal panel. In addition, since the long hole portion 2D is a long hole in the liquid crystal panel short side direction, the shaft portion 4D has a degree of freedom in the optical axis direction (z direction) and the liquid crystal panel short side direction (x direction).

  The spacer 4 includes an arm portion 4J shown in FIG. 6 and a coupling main body portion 4k as a main body portion, and two coupling main body portions 4k are connected via a spring-like arm portion 4J in the short side direction (x direction) of the liquid crystal panel. The coupling main body 4k can be independently moved in the optical axis direction. Then, by arranging two sets in the long side direction (y direction) of the liquid crystal panel, the liquid crystal panel can obtain movement in the optical axis direction and inclination freedom in the yaw and pitch directions.

  The surface 4A (FIG. 3) of the spacer 4 is in surface contact with the liquid crystal panel surface 3A, but the liquid crystal panel itself can freely move in a plane parallel direction while sliding with respect to the surface 4A of the spacer 4. There are degrees of freedom in the vertical, horizontal and rotational directions. That is, the liquid crystal panel has a degree of freedom in the six axis directions until UV bonding is performed.

  As a result, the liquid crystal panel can move freely, but the spacer 4 moves so as to follow the inner surface 2B, which is the bonding surface of the holding plate 2, and the surface 4A always tries to be parallel to the surface 3A. . For this reason, the adhesive thickness of an adhesion part can be made thin and a liquid crystal panel can be fixed firmly and highly accurately. The fact that the thickness of the adhesive layer is thin means that the adhesive is hardly contracted at the time of UV curing, and can be fixed while maintaining the adjusted position. When the adhesive layer is thick, the adhesive shrinks, and the liquid crystal panel moves to a shifted position during UV curing.

  No matter how much the adjustment accuracy is improved to the sub-micron level, if it is shifted in units of microns in this curing process, high-precision fixing cannot be realized. In addition, when the product is left in a high or low temperature environment, the internal strain remaining in the adhesive may be released and shift. Furthermore, when the adhesive layer is thick, it may be considered that the temperature is raised to near the glass transition temperature in a high temperature environment. On the other hand, if the adhesive layer is thin, the amount of adhesive that deforms is small even if the temperature is raised to near the glass transition point, so that the deviation can be made almost zero.

  FIG. 4 is a top view and a side view showing a state in which the spacer 4 is held on the holding plate 2. In the top view, the spacer 2 is offset by a spring 5 in the upward direction on the paper surface. The side view of FIG. 4 (the right side of FIG. 4) shows a form that regulates the spacer 4 from coming off in the upward direction on the paper surface. That is, the convex portion (claw-shaped portion) 4C of the spacer 4 is fitted into the concave portion 2C of the holding plate 2 to restrict the movement in the y direction.

  Further, the elongated hole portion 2D and the shaft portion 4D are also fitted, and are fitted in three places together with the fittings on both ends (the concave portion 2C and the convex portion 4C), and the coupling main body portion 4k of the spacer 4 (FIG. 6). Moves only in the optical axis direction (z direction), does not rotate, etc., and can maintain almost parallel to the surface 3A of the liquid crystal panel.

  Further, in the top view of FIG. 4, only the left or only the right of the spacer 4 may sink slightly. In this case, the shaft portion 4D moves in the long hole direction (x direction) of the long hole portion 2D. It is possible to follow. Although the surface 4A of the spacer 4 has a total of four locations, each sinks independently, and therefore can follow not only the optical axis direction of the liquid crystal panel but also the pitch and yaw directions.

Here, in FIG. 4, it will be described that the tilting (bowing) of the liquid crystal panel is suppressed. The designed liquid crystal panel surface is m0, the surface connecting the fitting positions on both ends (projection 4C and recess 2C) is m1, m0 including the center fitting position (shaft 4D and slot 2D), m0, m1 A plane parallel to is m2.
Here, since the height positions of the surface m1 and the surface m2 are different (heights from the surface m0 are H1 and H2, respectively), rotation (surface collapse) of the liquid crystal panel when m0 is regarded as the rotation axis can be suppressed. It becomes. When the surface m1 and the surface m2 are the same height, rotation (surface collapse) of the liquid crystal panel when m1 is regarded as a rotation axis cannot be suppressed.

  Next, the steps until the spacer 4 is held on the holding plate 2 will be described with reference to FIGS. The surface 4B of the spacer 4 is bonded to the inner surface 2B of the holding plate 2 with a UV adhesive, and the surface 4A is similarly bonded and fixed to the surface 3A of the liquid crystal panel (FIG. 3) with a UV adhesive. That is, on one end side and the other end side, the coupling main body portion 4k (FIG. 6) of the spacer 4 is a surface 4B as a first surface that adheres to the inner surface 2B of the holding plate 2 and a liquid place panel. And a second surface (as a surface 4A).

  Here, before attaching the spacer 4 to the holding plate 2, it is necessary to apply the UV adhesive to the surface 4B or the surface 2B. However, the spacer 4 (at least the arm portion 4j and the convex portion 4c) has a spring property (elastic force) in the spreading direction, and is applied to the surface 4B surface or the surface 2B when it is attached to the holding plate 2 as it is. The UV adhesive will be scraped off. Therefore, in the present embodiment, a layout is provided in which the inclined surface portion (chamfered portion) 4CM is provided on the surface 4C and the spacer 4 is included (held) inside the holding plate 2.

  FIG. 5 shows a state in which the spacer is now held by the two holding plates. UV adhesive has already been applied to the surfaces 4B on both ends. At this time, the spring 5 is held by the spacer 4. When the spacer is lowered from the state shown in FIG. 5 downward in the drawing, the state shown in FIG. 6 is obtained. When the inclined surface portion 4CM contacts the inner surface 2B of the holding plate 2, the entire spacer 2 is elastically deformed inward and moves downward along the surface 2B. At this time, the convex portion 4C contacts the surface 2B, but the surface 4B does not contact.

  That is, even if the adhesive is applied to the surface 4B, the surface 4B does not need to contact until it reaches a desired position. As a result, the UV adhesive applied to the surface 4B is not scraped off by the tip of the surface 2B, and reliably remains on the surfaces 4B and 2B. Further, in this embodiment, since the spacer 4 is included (held) inside the holding plate 2, it can be easily attached even with one finger.

  Then, after the UV adhesive is applied to the surface 4A and the liquid crystal panel 3 is brought closer, the UV adhesive enters between the surface 4A and the surface 3A, and the preparation before assembly adjustment is completed. Then, as a subsequent adjustment, the position of the liquid crystal panel is driven with high accuracy while confirming the projected image. When the position of the liquid crystal panel is determined, the UV adhesive applied between the surface 4B and the surface 2B and between the surface 4A and the surface 3A is simultaneously cured by irradiating UV light.

  The spacer 4 is a transparent body (translucent body) that can transmit UV light, and it is desirable that the connecting portion be elastically deformed, so that an acrylic material or the like is preferably selected. In general, the acrylic material is resin even if it is transparent, so it is difficult to transmit UV light. However, if a grade that transmits UV light as much as possible is selected, the fixing operation can be completed without problems. FIG. 1 shows that the fixing operation is completed in this way.

(Effect of this embodiment)
In the present embodiment, it is possible to realize a liquid crystal panel adjustment and holding structure that is more stable and reliable by eliminating workability, reliability of adhesive application, and variations in adhesive thickness as much as possible. That is, when the spacer member used for fixing the panel is bonded, it is not necessary to use a spacer holding jig, so that the UV irradiation in the UV bonding process is not obstructed. As a result, the UV adhesive can be cured stably and reliably, and the panel can be fixed with higher accuracy and reliability.

  In addition, the relative positional relationship between the prism and the panel can be fixed with high accuracy, and an image of a high-quality liquid crystal projector can be provided with very little registration deviation.

(Modification)
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

(Modification 1)
In the embodiment described above, a convex portion is provided outside the spacer 4 as the coupling member, and the spacer 4 is held inside the holding plate 2 as the holding member via the convex portion. However, the present invention is not limited to this, and the relationship between the inside and the outside of the holding member and the coupling member may be reversed.

(Modification 2)
In the embodiment described above, the reflection type has been described as the light modulation element, but may be a transmission type.

1 .... Prism 2 .... Holding plate 3 .... Liquid crystal panel unit 4 .... Spacer (coupling member) 4C ...

Claims (15)

A light modulation element;
A prism provided on the output side of the light modulation element;
A holding member for holding the prism;
A coupling member that couples the holding member and the light modulation element;
Have
One member of the holding member and the coupling member has a convex portion on the outside, and the one member is held inside the other member of the holding member and the coupling member via the convex portion. An image display device characterized by that.   The image display apparatus according to claim 1, wherein the convex portion is provided outside the coupling member, and the coupling member is held inside the holding member via the convex portion.   The image display apparatus according to claim 1, wherein two sets of the holding member and the coupling member are provided.   4. The image display device according to claim 1, wherein the other member of the holding member and the coupling member has a concave portion into which the convex portion is inserted. 5.   Of the holding member and the coupling member, the other member has one concave portion on one end side and the other end side, and the shaft portion of the coupling member is directly or indirectly in the central portion. The image display apparatus according to claim 4, further comprising a long hole portion to be inserted into the frame. Of the holding member and the coupling member, the one member has the convex portions on one end side and the other end side, respectively.
The first surface that adheres to the inner surface of the other member of the holding member and the coupling member and the second surface that adheres to the light modulation element on the one end side and the other end side, respectively. Having a main body with
6. The image display device according to claim 1, further comprising an arm portion between the one end portion side and the other end portion side.   The image display device according to claim 1, wherein the convex portion has a slope portion.   The said other member among the said holding member and the said coupling member WHEREIN: In order to suppress the surface tilt of the said light modulation element, the said recessed part and the said elongate hole part exist in a different height position. The image display device described.   The image display device according to claim 6, wherein the arm portion and the convex portion of the one member among the holding member and the coupling member have a spring property.   The image display apparatus according to claim 6, wherein at least one of the main members of the holding member and the coupling member is transparent.   The image display device according to claim 1, wherein the light modulation element is of a reflective type.   The image display device according to claim 11, wherein the prism is a polarization beam splitter.   The image display device according to claim 1, wherein the light modulation element is a transmissive type.   The image display device according to claim 1, wherein the light modulation element is a liquid crystal panel.   The image display apparatus according to claim 1, further comprising a projection optical system that projects an image by the light modulation element onto a projection surface.