JP2669372B2 - Dichroic mirror holder and method for fixing dichroic mirror - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dichroic mirror holder for holding a dichroic mirror at a predetermined position, tilt, etc. in a projection type liquid crystal display device and a method for fixing the dichroic mirror, and more particularly to a simple method. Despite the configuration,
The present invention relates to a dichroic mirror holder and a method for fixing the dichroic mirror, which can fix the dichroic mirror without distortion and thereby improve the image quality of a projected image.

[0002]

2. Description of the Related Art As shown in FIG. 4, a projection type liquid crystal display device splits a light beam emitted from a light source 1 into three light beams by a dichroic mirrors 2 and 3 and a reflection mirror 7, and then these light beams are dispersed. The liquid crystal display panels 8, 9 and 10 respectively corresponding to the three colors of R, G and B are projected, and then R, G and B emitted from these liquid crystal display panels 8, 9 and 10 are projected.
Images of the three colors are combined by dichroic mirrors 4, 5, and 6, and the combined images of R, G, B are projected onto the projection lens 11
Is projected onto a screen (not shown) through the interface, thereby forming a color image on the screen.

Here, the positions, inclinations, etc. of the dichroic mirrors 2 to 6 for separating the light of the light source and synthesizing the three-color images of R, G, and B have a significant effect on the formation of the projected image. Yes, conventionally, these dichroic mirrors 2-6
Was fixed to the dichroic mirror holder to hold an appropriate position and inclination in the projection type liquid crystal display device.

Hereinafter, a conventional dichroic mirror holder will be described with reference to FIGS. FIG. 5 is a perspective view showing a conventional dichroic mirror holder, and FIG. 6 is a partially enlarged sectional view showing a fixed state of the dichroic mirror by the conventional dichroic mirror holder.

As shown in these drawings, the conventional dichroic mirror holder 100 is composed of a frame holder body 110 and a plate-shaped pressing plate 120. Here, the holder body 110 includes the dichroic mirror 2
A step portion 111 for mounting (to 6) is formed, and the height difference of the step portion 111 is slightly smaller than the wall thickness of the dichroic mirror 2 (to 6).

In such a conventional dichroic mirror holder 100, the dichroic mirror 2 (to 6) is placed on the stepped portion 111 of the holder body 110, and then the holder body 1 is placed.
The pressing plates 120 were screwed to predetermined four positions of 10 and the dichroic mirror 2 (to 6) was fixed to the holder main body 110 by the elastic force of these pressing plates 120.

[0007]

As described above, in the projection type liquid crystal display device, the R, G, B images are reflected by the dichroic mirrors 2 to 6, and the R, G, B images are respectively reflected. Projection lens 11 passing through different optical paths
Therefore, if the dichroic mirrors, especially the dichroic mirrors 4, 5, and 6 for synthesizing the R, G, and B images are distorted, the R, G, and B images are distorted. This is undesirable.

However, in the conventional dichroic mirror holder described above, the dichroic mirrors 2 (to 6) are pressed by the plurality of pressing plates 120, and the holder body 11 is pressed.
Since it is fixed to 0, the dichroic mirror 2 (to 6), the step portion 111 and the pressing plate 120 are in surface contact with each other, and the dichroic mirror 2 (to 6).
Undulations on the contact surface between the step 111 and the pressing plate 120 propagate to the dichroic mirror 2 (（6), thereby distorting the dichroic mirror 2 (〜6). There was a problem.

That is, in general, even if the dichroic mirror is not fixed to the dichroic mirror holder,
A slight distortion has already occurred due to the surface accuracy of the glass forming this and the heating at the time of vapor deposition. FIG. 7 shows distortion of a single dichroic mirror by interference fringes, and each interference fringe shows a height difference of about 3 μm. As shown in the figure, the distortion of the single dichroic mirror 2 (〜6) is usually concentric with a certain portion as the center. The adverse effects are small.

However, when the dichroic mirror 2 (to 6) is fixed to the conventional dichroic mirror holder 100,
The waviness of the contact surface between the step portion 111 and the pressing plate 120 propagates to the dichroic mirror 2 (to 6), and the dichroic mirror 2 (to 6) partially deteriorates in surface accuracy as shown in FIG. There was uneven strain due to.

Such a dichroic mirror 2 (to 6)
Due to the non-uniform distortion, there is a problem that the resolution of the projected image is deteriorated, the image is distorted, and a color shift is caused by the distortion of the image. There is also a problem that the adverse effect on these projected images becomes more remarkable depending on the strength of the stress of the pressing plate 120.

Although it is not for fixing the dichroic mirror, in JP-A-61-32533, a projection is provided on the film lead and a through hole or a recess is formed in the projection. Inject the adhesive into
A semiconductor device has been proposed in which the lead film is bonded to the electrodes of the semiconductor element.

It is conceivable that the joining means of the film lead and the semiconductor element in this semiconductor device is applied to the fixing of the dichroic mirror and the dichroic mirror holder, but the dichroic mirror is in surface contact with the step portion 111 as in the conventional case. This causes the same problem as the dichroic mirror holder 100.

In Japanese Utility Model Application Laid-Open No. 4-105592, there is provided means for mounting a metal substrate on which an electric circuit is mounted in a case, wherein a plurality of protrusions are formed on a joint surface of the case with the metal substrate. When the substrate is placed on the bonding surface,
A case mounting means for a metal substrate has been proposed in which a gap between the joint surface formed by these protrusions and the metal case is filled with an adhesive, and the entire periphery of the metal substrate is fixed to the joint surface.

However, such fixing (mounting) means is
When applied to fixing the dichroic mirror and the dichroic mirror holder, one of the surfaces of the dichroic mirror is not held at all, and the dichroic mirror may be detached from the dichroic mirror holder. Further, since the bonding area is very large, there is a problem that the dichroic mirror is distorted due to the curing and shrinkage of the adhesive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple structure, and can fix a dichroic mirror without distortion, thereby improving the image quality of a projected image. The present invention relates to a dichroic mirror holder and a method of fixing the dichroic mirror.

[0017]

To achieve the above object, a dichroic mirror holder according to claim 1 is a dichroic mirror holder for holding a dichroic mirror of a projection type liquid crystal display device. It is a frame body that surrounds the
Within this step, place the specified part of the dichroic mirror.
It is attached to the holder body with a predetermined gap between the holder body provided with a projection having a spherical tip for supporting and the dichroic mirror, and the dike
A holding plate formed with through-holes at a position opposite to the projection via the lock mirror, the through-hole of the holding plate
Injected into the gap from the front of the dichroic mirror
The structure includes a portion supported by the projection and an adhesive for holding a portion on the opposite side .

The dichroic mirror holder according to a second aspect of the present invention is configured such that the height difference of the step portion is larger than the sum of the thickness of the dichroic mirror and the height of the protrusion.

According to the method of fixing the dichroic mirror according to the third aspect, the dichroic mirror is provided at a plurality of positions on the stepped portion of the holder body .
The dichroic mirror is placed on the projection of the tip spherical surface, and then a plurality of through holes formed in the holding plate are attached to the plurality of through holes.
The holding plate is attached to the holder main body so as to face the protrusions, and then an adhesive is injected between the dichroic mirror and the holding plate through the plurality of through holes so that the holding plate and the dichroic mirror are inserted. There is a method of fixing the dichroic mirror by holding a plurality of positions on the peripheral edge of the dichroic mirror by the adhesive cured in the gap and the protrusions.

[0020]

According to the dichroic mirror and the method for fixing the dichroic mirror of the present invention having the above structure, the dichroic mirror is fixed to the dichroic mirror by the adhesive injected from the through hole between the holding plate and the dichroic mirror. Since it is fixed to the mirror holder, the pressure pressing the dichroic mirror is extremely small, and the stress applied to the dichroic mirror can be reduced as much as possible.

Further, since the dichroic mirror is fixed by the adhesive having a small area and the projection having the spherical tip, it becomes possible to support the dichroic mirror by point contact. The influence on the surface accuracy of the dichroic mirror can be minimized.

Therefore, it is possible to fix the dichroic mirror without distorting, and it is possible to prevent the degradation of the resolution of the projected image, the distortion of the image, and the occurrence of color shift due to the distortion of the image. The image quality of the image can be improved.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a dichroic mirror holder and a method of fixing a dichroic mirror according to the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a perspective view showing a dichroic mirror holder according to this embodiment. FIG. 2 is a partially enlarged sectional view showing a fixed state of the dichroic mirror by the dichroic mirror holder. First, an embodiment of the dichroic mirror holder will be described.

As shown in FIG. 1, the dichroic mirror holder 10 of this embodiment is composed of a frame holder main body 11 and four plate-like holding plates 12.

As shown in FIG. 2, inside the holder body 11, a stepped portion 11a for mounting the dichroic mirror 2 (to 6) is formed. And this step 11
The height difference of a is set to a size obtained by adding about 1 mm to the total of the thickness of the dichroic mirror 2 (to 6) and the height of the projections 11b (11c, 11d, 11e) described later.

Due to such a height difference of the stepped portion 11a, when the dichroic mirror 2 (to 6) is fixed,
A gap of about 1 mm is formed between the holding plate 12 and the dichroic mirror 2 (（6). The protrusions 11b, 1 having spherical tip ends are provided at four predetermined positions of the step portion 11a.
1c, 11d and 11e are provided.

Further, when attached to the holder body 11, each of the holding plates 12 has each of the projections 11b, 11c, 11c.
Through holes 12a are formed so as to face d and 11e, respectively. Further, an appropriate amount of adhesive 13 for fixing the dichroic mirror 2 (to 6) is injected into each through hole 12a.

Next, an embodiment of a method for fixing the dichroic mirror will be described. First, the dichroic mirror 2 (（6) is placed on the step portion 11a of the holder body 11. Then, the dichroic mirror 2 (to 6) has the projections 11b,
It is supported by 11c, 11d, and 11e. Next, the holding plate 12 is attached to the holder body 11 so that the protrusions 11b, 11c, 11d, 11e and the through holes 12a face each other, and then the adhesive 13 is injected into the through holes 12a.

Then, the adhesive 13 hardened between the holding plate 12 and the dichroic mirror 2 (（6) and the projections 11b, 11c, 11d, 11e form the periphery of the dichroic mirror 2 (〜6). Four places are kept,
As a result, the dichroic mirrors 2 to 6 are fixed to the dichroic mirror holder 10.

According to the dichroic mirror holder and the method of fixing the dichroic mirror of this embodiment, the holding plate 12 and the dichroic mirror 2 are inserted from the through hole 12a.
The dichroic mirror 2 (to 6) is fixed to the dichroic mirror holder 10 by the adhesive 13 injected between (to 6).
Since it was fixed to the dichroic mirror 2 (~
The pressure for pressing 6) is extremely small, and the stress applied to the dichroic mirror 2 (to 6) can be reduced as much as possible.

Since the dichroic mirror 2 (.about.6) is fixed by the adhesive 13 having a very small area and the projections 11b, 11c, 11d and 11e having spherical tips, the dichroic mirror 2 (.about.6) is fixed. ) Can be supported by point contact, which allows the dichroic mirror 2 to be supported.
It is possible to minimize the influence of (to 6) on the surface accuracy.

Therefore, according to the dichroic mirror holder and the method for fixing the dichroic mirror of the above embodiment,
The dichroic mirrors 2 to 6 can be fixed without being distorted, and it is possible to prevent the degradation of the resolution of the projected image, the distortion of the image, and the occurrence of color shift due to the distortion of the image. The image quality of the image can be improved.

Here, the inventor has found that the size of the dichroic mirror is 90 mm × 10 mm, the wall thickness is 1.5 mm, the height difference of the step portion is 2.5 mm, the through hole of the holding plate is 2 mm in diameter. When the dichroic mirror was fixed by the holder and the surface accuracy of the dichroic mirror was measured, it was found that the deterioration of the surface accuracy of the dichroic mirror could be reduced to about 50% of the conventional level.

Further, the dichroic mirror holder and the dichroic mirror were mounted on a projection type liquid crystal display device having a liquid crystal display panel having a pixel size of 90 μm, and the color shift of the projected image was measured. It was found that the color shift of the image can be reduced to ¼ pixel or less.

The dichroic mirror holder and the method for fixing the dichroic mirror according to the present invention are not limited to the above embodiment.

In the above embodiment, the four protrusions 11b, 11
c, 11d, 11e, the dichroic mirror 2 (~
Although the configuration 6) is supported at four points, the configuration is not particularly limited, and the configuration may be such that the dichroic mirror 2 (６6) is supported by three or five or more projections. . However, dichroic mirror 2 (~
When the shape of 6) is a quadrangle, the four protrusions 11b, 11 which have few contact points and can be stably fixed.
Support by c, 11d and 11e is preferred.

In the above-mentioned embodiment (experimental example), the gap formed between the holding plate 12 and the dichroic mirror 2 (to 6) is about 1 mm, and the through hole of the holding plate has a diameter of 2 mm.
However, these dimensions may be appropriately changed depending on the properties of the adhesive used.

Further, in the above embodiment, the height difference of the step portion 11a is made larger than the sum of the thickness of the dichroic mirror 2 (（6) and the height of the projections 11b (11c, 11d, 11e), and is held Plate 12 and dichroic mirror 2
Between (-6), a gap for injecting the adhesive 13 was formed.

However, in addition to this structure, the distance between the front surface of the stepped portion 11a and the back surface of the holding plate 12 is determined by the thickness of the dichroic mirror 2 (to 6) and the projection 11b (11).
If the structure can be made larger than the total height of (c, 11d, 11e), the gap can be formed between the holding plate 12 and the dichroic mirror 2 (to 6) as in the above embodiment.

For example, as shown in FIG. 3, the holding plate 12 has a through hole 12a with a projection 11b (11c, 11c).
It may be formed by bending so as to be located above the dichroic mirror corresponding to d, 11e) and form the gap between the holding plate 12 and the dichroic mirror 2 (to 6).

[0041]

As described above, according to the dichroic mirror holder and the method for fixing the dichroic mirror of the present invention, the stress applied to the dichroic mirror is minimized and the dichroic mirror is formed by point contact. Since the dichroic mirror is fixed, the dichroic mirror can be fixed without distorting, thereby preventing degradation of the resolution of the projected image, distortion of the image, and occurrence of color shift due to the distortion of the image. Therefore, the image quality of the projected image can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a dichroic mirror holder according to one embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a fixed state of a dichroic mirror by the dichroic mirror holder.

FIG. 3 is a partially enlarged sectional view showing a dichroic mirror according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a general projection type liquid crystal display device.

FIG. 5 is a perspective view showing a conventional dichroic mirror holder.

FIG. 6 is a partially enlarged sectional view showing a fixed state of a dichroic mirror by a conventional dichroic mirror holder.

FIG. 7 is an explanatory diagram showing the distortion of a single dichroic mirror not fixed to the dichroic mirror holder by interference fringes.

FIG. 8 is an explanatory diagram showing the distortion of a dichroic mirror fixed to a conventional dichroic mirror holder by interference fringes.

[Explanation of symbols]

 2, 3, 4, 5, 6 Diclock mirror 10 Diclock mirror holder 11 Holder main body 11a, 12b Stepped portion 11b, 11c, 11d, 11e Projection 12 Holding plate 12a Through hole 13 Adhesive

Claims (3)

(57) [Claims] 1. A dichroic mirror holder for holding the dichroic mirror of the projection type liquid crystal display device, a frame body surrounding said dichroic mirror, to form a stepped portion on the inner side, in the step portion, the die a holder body having a projecting end which has a spherical surface for supporting a predetermined portion of the clock mirror, attached to the holder main body with a predetermined gap between the dichroic mirror and the dichroic
A holding plate having a through hole formed at a position facing the protrusion through a mirror, and a portion injected into the gap from the through hole of the holding plate and supported by the protrusion of the dichroic mirror .
A dichroic mirror holder comprising: 2. The dichroic mirror according to claim 1, wherein the height difference of the step portion is larger than the sum of the thickness of the dichroic mirror and the height of the protrusion. 3. The holder body is provided at a plurality of steps on the stepped portion .
A dichroic mirror is placed on the protrusion of the tip spherical surface , and then a plurality of through holes formed in the holding plate
The holding plate is attached to the holder main body so as to face a plurality of protrusions, and then an adhesive is injected between the dichroic mirror and the holding plate through the plurality of through holes to dispose the holding plate and the die. Fixing the dichroic mirror by holding the dichroic mirror at a plurality of locations on the periphery of the dichroic mirror by the adhesive cured in the gap between the clock mirrors and the protrusions. Method.