JP2001056502A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a situation that mechanical stress is exerted on a dichroic mirror by thermal expansion or thermal contraction and the plane of the dichroic mirror is distorted. SOLUTION: In this projection type display device 1, a base plate 31 is constituted of glass having the same coefficient of thermal expansion as the dichroic mirrors 4 and 5 constituted of the glass, and a polarizing beam splitter 3, the dichroic mirrors 4 and 5, reflection type light valves 9, 10 and 11 are placed on the base plate 31, and the dichroic mirrors 4 and 5 are stuck to the base plate 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device most suitable for application to a projector device for projecting a full-color image on a screen or the like, and particularly to a projection type display device using a polarizing beam splitter and a dichroic mirror. The present invention belongs to a technical field related to a device for positioning and holding a dichroic mirror or the like of a projection type display device of a reflection type light valve system for performing color separation and color synthesis with high precision.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open Nos. Hei 6-175123 and Hei 10-26756 disclose, and as shown in FIGS. 8 and 9, a polarizing beam splitter and a dichroic mirror are used. There is a projection display device 1 applied to a projector device that projects a full-color video image on a screen or the like by a reflective light valve system that performs color separation and color synthesis. The projection display apparatus 1 includes a light source 2, a polarizing beam splitter 3, two dichroic mirrors 4 and 5, which are reflection mirrors for color separation, and three quarter-wave plates 6, 7, and 8. And three reflective light valves 9, 10, 11 and a projection lens 12. Then, the light L1 close to the parallel light emitted from the light source 2 is incident on the polarization beam splitter 3, and the light L1 is incident on the polarization separation unit 3a inside the polarization beam splitter 3 at 45 °. And P in the light L1
The polarization component light L2 becomes unnecessary light that is transmitted through the polarization separation unit 3a and emitted into the device. On the other hand, S in the light L1
The polarization component light L3 is polarized at 90 ° by the polarization separation section 3a and is reflected to the side opposite to the projection lens 12. Then, the S-polarized component light L3 is converted into two dichroic mirrors 4,
5 and sequentially separated by these dichroic mirrors 4 and 5.

That is, the blue light L in the S-polarized component light L3
B3 is color-separated and reflected by the first dichroic mirror 4, passes through the quarter-wave plate 6 for blue light, and enters the reflective light valve 9 for blue light. Then, the red light LR3 and the green light LG3 in the S-polarized light L3 pass through the first dichroic mirror 4 and enter the second dichroic mirror 5. And that S
The red light LR3 in the polarization component light L3 is color-separated and reflected by the second dichroic mirror 5, and is divided by 1 / red for the red light.
Reflective light valve 1 for red light transmitted through four-wavelength plate 7
, The green light LG3 is transmitted through the second dichroic mirror 5, and the green light LG3 is a １ ／ wavelength plate 8 for green.
And enters the reflective light valve 11 for green.

In this way, the blue light of the S-polarized component light L3 that has been color-separated by the two dichroic mirrors 4 and 5 and incident on the three reflection-type light valves 9, 10 and 11, respectively, in this way. LB3, red light LR3, green light L
G3 is modulated into image light L4 of blue light LB4, red light LR4, and blue light LG4 by image signals input to the reflection type light valves 9, 10 and 11, respectively, reflected in the opposite direction of the incident direction, and emitted. You. At this time, the three reflective light valves 9, 10, and 11 have a high reflectance, and the black portions of the image reflect without rotating the polarization planes of the incident blue light LB3, red light LR3, and green light LG3. Then, in the white portion of the image, modulation is performed by the input image signal so that the polarization planes of the incident blue light LB3, red light LR3, and green light LG3 are rotated by 90 °.

Accordingly, three reflective light valves 9, 1
Blue light LB modulated and reflected at 0 and 11 respectively
4, the polarization planes of the image light L4 of the red light LR4 and the green light LG4 are rotated by 90 °, and these image light L4 are transmitted through the quarter-wave plates 6, 7, and 8, respectively, and are two dichroic mirrors. The light is reflected and transmitted by 4, 5 and color-combined, and is returned to the polarization beam splitter 3a of the polarization beam splitter 3. However, since the polarization plane of the color-combined image light L4 is rotated by 90 °, the image light L4 is not returned to the light source 2 and the polarization separation unit 3 of the polarization beam splitter 3
a is transmitted as it is, and is projected as a full-color image formed on the screen or the like by the projection lens 12.

[0006]

However, this type of conventional projection display device 1 has not yet been put on a commercial basis at present. The greatest reason is that the two dichroic mirrors 4 and 5 are made of multi-coated thin glass, and the two dichroic mirrors 4 and 5 are liable to generate a plane distortion due to thermal expansion or thermal contraction. , The difficulty of mounting. Therefore,
As a conventionally known technique, as shown in FIG. 10, a die cast frame 21 which is a cast part of aluminum having a thermal expansion coefficient close to that of glass is cast, and the polarizing beam splitter 3 and the thin glass Dichroic mirrors 4, 5, 3
A quarter-wave plate 6, 7, 8; a reflective light valve 9;
It is possible to consider a system in which the projection lenses 10 and 11 and the projection lens 12 are mounted. At this time, in particular, in order to accurately attach the two dichroic mirrors 4 and 5 to the die-cast frame 21, the mirror mounting surface 22 is cut into the die-cast frame 21 and the plurality of screws 23 are attached to the die-cast frame 21. A plurality of leaf springs 24 with screws
Then, it can be considered that the dichroic mirrors 4 and 5 are elastically pressed and fixed to the mirror mounting surface 22, respectively.

However, in reality, the mirror mounting surface is caused by mechanical stress such as tension or compression generated between the die cast frame 21 and the dichroic mirrors 4 and 5 due to thermal expansion and thermal contraction of the die cast frame 21. As a result, the dichroic mirrors 4 and 5 are distorted in a plane. As a result, the blue light LB4, the red light LR4, and the green light L of the color-combined image light L4
The G4 image cannot be accurately superimposed, and the image projected so as to be formed on a screen or the like is liable to cause a color shift or the like due to a shift of each pixel.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is an object of the present invention to provide a projection type display device in which a dichroic mirror is unlikely to have a plane distortion due to thermal expansion or thermal contraction. It is an object.

[0009]

In order to achieve the above object, a projection type display device according to the present invention comprises a substrate on which at least a polarizing beam splitter, a dichroic mirror and a reflection type light valve are mounted, and a thermal expansion of the dichroic mirror. It is composed of a member having the same or almost the same coefficient of thermal expansion as the coefficient.

[0010] The projection display apparatus of the present invention having the above-described structure is characterized in that at least a polarizing beam splitter, a dichroic mirror, and a reflective light are formed on a substrate made of a member having the same or substantially the same thermal expansion coefficient as that of a dichroic mirror. Since the valve is mounted, almost no mechanical stress occurs due to thermal expansion or thermal contraction between the dichroic mirror and the substrate, and the plane accuracy of the dichroic mirror can be maintained as high as possible. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a projection display apparatus in which the present invention is applied to a projector apparatus will be described below in the following order with reference to FIGS. 9 and 10
The same components as those described above are denoted by the same reference numerals, and redundant description will be omitted. (1) ... Description of the first embodiment (2) ... Description of the second embodiment (3) ... Description of the third embodiment (4) ... Fourth embodiment Description

(1)... Description of the First Embodiment First, the first embodiment of the projection type display device 1 will be described with reference to FIGS. 1 to 3. First, a polarizing beam splitter 3 and two dichroics will be described. 1/4 of mirrors 4, 5, 3
4 wavelength plates 6, 7, 8, 3 reflective light valves 9, 1
0, 11 and a horizontal substrate 31 on which the projection lens 12 is mounted; a plurality of columns 32, 33, such as plates and prisms, which are vertically attached to a plurality of positions on the substrate 31; And a top plate 34 placed substantially in parallel (being horizontal) at a predetermined height above the substrate 31 by the columns 32 and 33. And these substrates 31,
The plurality of pillars 32 and 33 and the top plate 34 are members that are members having the same or substantially the same thermal expansion coefficient as the two thermal expansion coefficients of the two dichroic mirrors 4 and 5 made of multi-coated thin glass. Alternatively, it is made of a member having the same or almost the same coefficient of thermal expansion as glass.

The substrate 31 and the plurality of columns 3
2, 33 and the top plate 34 are formed by means such as pressurization, extrusion, injection or the like. In particular, the upper surface 31a of the substrate 31, the lower surface 34a of the top plate 34, and the upper and lower end surfaces of the plurality of columns 32, 33 are formed. The surface is processed with high precision by polishing or the like. Then, a plurality of columns 32, 33 are vertically adhered on the upper surface 31a of the substrate 31 so as not to obstruct the optical path by their lower ends, and the lower surface of the top plate 34 is placed on the upper ends of the plurality of columns 32, 33. The substrate 31 and the top plate 34 are assembled in parallel with high precision by bonding the substrate 34a horizontally.

A polarizing beam splitter 3, two dichroic mirrors 4, 5, three の wavelength plates 6,
7, 8, and three reflective light valves 9, 10, 11 and a projection lens 12 are attached to a top plate 33 above the substrate 31 by bonding or the like. At this time, the polarizing beam splitter 3 has a side surface on the side of the projection lens 12 and a side surface opposite to the light source 2 by a plate-like column 32 and a positioning member 36 adhered on the upper surface 31a of the substrate 31 so as not to disturb the optical path. And are horizontally adhered onto the substrate 31.

Then, two dichroic mirrors 4,
Each of a plurality of small projections and a pair of positioning members 37 each formed of a long square pillar-shaped member having the lower ends 4a, 5a of 5 horizontally bonded on the upper surface 31a of the substrate 31 so as not to obstruct the optical path. It is adhered and positioned and fixed so as to be sandwiched between the positioning member 38 from both sides. The upper ends 4b and 5b of these two dichroic mirrors 4 and 5 are integrally formed on the lower surface 34a of the top plate 34 so as not to obstruct the optical path. The dichroic mirrors 4 and 5 are slidably inserted and positioned. The dichroic mirrors 4 and 5 are vertically mounted so as to be sandwiched between the substrate 31 and the top plate 34 from above and below.

At this time, the positioning members 36, 37, 38 are made of glass or a glass having the same or almost the same coefficient of thermal expansion as the substrate 31, the plurality of columns 32, 33 and the top plate 34, or the same or almost the same as glass. The positioning members 36, 37, and 38 are formed by means of pressure, extrusion, injection, or the like, similarly to the substrate 31, the plurality of columns 32, 33, and the top plate 34. ing. And especially, the bottom surfaces 37a, 38 of the positioning members 37, 38
a and one of the side surfaces 37b, 38b are flattened with high precision by polishing or the like.
One corner of 38a and side surfaces 37b and 38b are each formed at 90 °. Also, upper and lower ends 4a, 4b, 5a, 5b of the two dichroic mirrors 4, 5
c, 4d, 5c, and 5d are also planarized with high precision by polishing or the like. A pair of positioning members 37 are adhered on the upper surface 31a of the substrate 31 with high precision at the bottom surface 37a, and the lower ends 4 of the two dichroic mirrors 4 and 5 are fixed.
One of the side surfaces 4c and 5c of the pair of positioning members 37 is bonded to one side surface 37b of the pair of positioning members 37. Further, a plurality of positioning members 38 are respectively provided on the bottom surface 38 a of the substrate 3.
1 is bonded to the upper surface 31a, and one side surface 38b is
The lower ends 4a, 5a of the dichroic mirrors 4, 5 are adhered to the other side surfaces 4d, 5d. Therefore, in particular,
The lower ends 4a and 5a of the two dichroic mirrors 4 and 5 are adhered to the substrate 31 in a state where the lower ends 4a and 5a are sandwiched from both sides between a pair of long positioning members 37 and a plurality of positioning members 38 which are small projections. The vertical degree of the dichroic mirrors 4 and 5 with respect to the substrate 31 is set with high precision, and a high attachment strength to the substrate 31 is obtained.

The two dichroic mirrors 4, 5
Top plate 34 in which upper ends 4b and 5b of the top plate are slidably inserted.
A pair of vibration-resistant cushion members 42 made of an elastic material such as urethane resin are attached to both sides of the two dichroic mirrors 4 and 5 in the pair of groove portions 41. , 5 upper end 4b, 5
The two side surfaces 4c, 4d, 5c, and 5d of b are elastically held by the pair of cushion members 42. Therefore, the side surfaces 4c, 4d, 5c, and 5d of the upper ends 4b and 5b of the dichroic mirrors 4 and 5 do not directly contact the pair of convex portions 40 of the top plate 34. The dichroic mirrors 4 and 5 are not damaged by vibration during transportation or the like, and the safety is high.

The three reflective light valves 9, 1
0 and 11 are the upper surface 31 a of the substrate 31 and the lower surface 34 of the top plate 34.
a is vertically mounted between the substrate 31 and the top plate 34 by a pair of upper and lower mounting brackets 43 and 44 which are bonded to each other so as not to obstruct the optical path. Reference numerals 7 and 8 denote respective reflection type light valves 9 and 1.
It is attached to the front surfaces of 0 and 11 by bonding or the like. The projection lens 12 is mounted in a lens holder 45 buried in the plate-like column 32.

The three reflective light valves 9, 1
Reference numerals 0 and 11 are mounted on a holding substrate 43a and held by a holding bracket 43b so as to be freely angle-adjustable via a six-axis adjustment mechanism (not shown), and a pair of upper and lower mounting brackets 43 and 44 are used by these holding brackets 43b. Attached to. At this time, it is preferable that the lower ends of the respective holding brackets 43b are attached to the lower mounting bracket 43 by bonding or the like, and the upper ends of these holding brackets 43b are mounted on the upper mounting bracket 44 so as to be slidable in the vertical direction. . Then, the light L1 emitted from the light source 2 (not shown) is incident on the polarization beam splitter 3a of the polarization beam splitter 3 at almost 45 °, and as described with reference to FIG.
The image light L4 of the blue light LB4, the red light LR4, and the green light LG4 modulated and reflected at 0 and 11 are combined by the two dichroic mirrors 4 and 5 so as to form an image on a screen or the like by the projection lens 12. And the blue light LB
4. The respective holding substrates 43a are adjusted by the respective six-axis adjustment mechanisms of the three reflection type light valves 9, 10 and 11 so that the image light L4 of the red light LR4 and the green light LG4 is accurately superimposed on the screen. Each holding substrate 4
Adjust the angle with respect to 3b. Then, after the angle adjustment, the respective holding substrates 43a are completely fixed to the holding metal members 43b by fixing means such as soldering, and a series of assembling work is completed.

According to the first embodiment of the projection display apparatus 1 configured as described above, the substrate 31, the plurality of columns 32, 33, the top plate 34, the positioning members 36, 37, 38.
The convex portions 40 and the like are made of the same glass as the two dichroic mirrors 4 and 5 made of thin glass, or a member having the same or almost the same coefficient of thermal expansion as glass. Mechanical stress such as tension and compression due to shrinkage is caused by these two dichroic mirrors 4 and 5.
Hardly occurs between the substrate 31 and the top plate 43 or the like. In other words, the two dichroic mirrors 4 and 5 have the same or almost the same thermal expansion coefficient as the substrate 31, the plurality of columns 32 and 33, the top plate 34, the plurality of positioning members 36, 37 and 38, and the convex portion 40. Due to expansion and thermal contraction, almost no mechanical stress is applied between the two dichroic mirrors 4, 5 and the substrate 31, the top plate 43, or the like.

In particular, the two dichroic mirrors 4 and 5 have only their lower ends 4a and 5a positioned and adhered to the substrate 31 with high precision by positioning members 37 and 38. Since the upper ends 4b and 5b of the mirrors 4 and 5 are slidable in the grooves 39 formed on the lower surface 43a of the top plate 43 and are elastically held by the cushion member 42, these dichroic mirrors 4 and 5 Only the lower ends 4a, 5a are fixed on the substrate 31, so-called cantilevered support. Therefore, even if the vertical length changes due to the thermal expansion and thermal contraction of the plurality of columns 32 and 33, and the vertical distance between the substrate 31 and the top plate 34 changes, the mechanical stress caused by these changes occurs. Is not added to the dichroic mirrors 4, 5.

As described above, almost no mechanical stress is applied to the two dichroic mirrors 4 and 5 due to thermal expansion and thermal contraction, and almost no plane distortion of the dichroic mirrors 4 and 5 is caused. Since these hardly occur, the planar accuracy can be maintained as high as possible. Moreover, the polarizing beam splitter 3, the quarter-wave plates 6, 7, 8, the reflection type light valves 9, 10, 11 and the projection lens 12 are mounted on the same glass substrate as the dichroic mirrors 4, 5 by bonding or the like. , The mutual positions of the polarizing beam splitter 3, the dichroic mirrors 4, 5, 1/4 wavelength plates 6, 7, 8, the reflection type light valves 9, 10, 11 and the projection lens 12 due to thermal expansion and contraction. Almost no misalignment occurs.

Therefore, according to the first embodiment of the projection type display device 1, a full-color image projected so as to form an image on a screen or the like is almost not adversely affected by thermal expansion or thermal contraction. Therefore, the pixels of the blue light LB4, the red light LR4, and the green light LG4 of the full-color image can be accurately overlapped. Therefore, there is no occurrence of color shift due to a shift of each pixel of a full-color image projected on a screen or the like, and a high-quality projection display device capable of constantly projecting a high-quality image stably for a long period of time. 1 can be realized.

(2) Description of Second Embodiment Next, a second embodiment of the projection type display device 1 will be described with reference to FIG. 4. In this case, the first embodiment will be described. A pair of positioning members 37, which are long prismatic members, are replaced by a pair of positioning members 47, which are long triangular prism members. The bottom surface and one side surface of the positioning member 47 are positioning members. As in the case of 37, the surface is processed with high precision by polishing or the like, and one corner thereof is formed at 90 °. The pair of positioning members 47 are made of glass or a member having the same or almost the same thermal expansion coefficient as glass, and the bottom surfaces of these positioning members 47 are adhered to the upper surface 31a of the substrate 31, and the positioning members 47, the lower end 4a of dichroic mirrors 4, 5
The side surfaces 4c and 5c of 5a are bonded. The other configuration is the same as that of the first embodiment. In this case, since the positioning member 47 is formed of a triangular prism-shaped member, the two surfaces that are bonded to the substrate 31 and the dichroic mirrors 4 and 5 and that are flat-processed with high precision by polishing or the like are used. Compared with the positioning member 37 of a quadrangular prism-shaped member, it is easy to clearly determine and the operability of assembly can be improved, so that there is a feature that the practicability is high.

(3) Description of Third Embodiment Next, a third embodiment of the projection type display device 1 will be described with reference to FIGS. 5 and 6. In this case, the first and second embodiments will be described. A pair of positioning members 37 and 47 shown in the second embodiment are also used as a positioning member 48 which is a single thick plate-like member, and the bottom surface and both side surfaces of the positioning member 48 are respectively polished or the like. The plane is machined with high precision, and the two corners are formed at 90 °. And this positioning member 4
Numeral 8 is made of glass or a member having the same or almost the same coefficient of thermal expansion as glass, the bottom surface of the positioning member 48 is adhered to the upper surface 31a of the substrate 31, and two sheets are provided on both side surfaces of the positioning member 48. The dichroic mirrors 4 and 5 have lower ends 4a and 5a adhered to side surfaces. Other configurations are the same as those of the first and second embodiments.
In this case, since the positioning member 48 is in the form of a thick plate, the three surfaces which are adhered to the substrate 31 and the dichroic mirrors 4 and 5 and which are plane-processed with high precision by polishing or the like are formed into a square pillar shape. It is easier to determine clearly than the positioning member 37. In addition, a pair of positioning members 37, 47
By using a single positioning member 48, the number of parts and the number of assembling steps can be reduced, so that the cost can be reduced and the workability of assembling can be improved.

(4)... Description of Fourth Embodiment Next, referring to FIG. 7, a fourth embodiment of the projection type display apparatus 1 will be described. In this case, the first to third embodiments will be described. A plurality of small projection-shaped positioning members 38 shown in the embodiment are all omitted, and the positioning member 48, which is a single thick plate-shaped member shown in the third embodiment, is attached to the substrate 31 by the bottom surface.
Is precisely adhered to the upper surface 31a of the
Two dichroic mirrors 4 on both sides
The side surfaces 4c and 5c of a and 5a are bonded with high precision. The other configuration is the same as the first to third embodiments. In order to bond the two dichroic mirrors 4 and 5 on the substrate 31 with high accuracy, a high-precision robot is required. However, when the projection display device 1 is mass-produced, The bottom surface and one side surface of the positioning member 38, which is a plurality of small projections, can be omitted from the preliminary processing step for fitting the surface to 90 ° with high precision by polishing or the like. Since the step of bonding on top can be omitted, the first to third
There is a feature that the overall cost can be reduced as compared with the embodiment.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical concept of the present invention.

[0028]

The projection display apparatus of the present invention having the above-described structure can provide the following effects.

According to a first aspect of the present invention, at least a polarizing beam splitter, a dichroic mirror and a reflection type light valve are mounted on a substrate made of a member having the same or almost the same coefficient of thermal expansion as a dichroic mirror. Since almost no mechanical stress due to thermal expansion or thermal contraction occurs between the substrate and the substrate, the plane accuracy of the dichroic mirror can be maintained as high as possible. The blue, red, and green light pixels of the full-color image are accurately superimposed on the full-color image projected so that the image is almost unaffected by thermal expansion and contraction. be able to. Accordingly, a high-quality projection display device capable of constantly and stably projecting a high-quality image for a long time without causing a color shift or the like due to a pixel-by-pixel shift of a full-color image projected on a screen or the like. Can be realized.

According to a second aspect of the present invention, at least the positioning member of the dichroic mirror is adhered to the substrate, so that the positioning of the dichroic mirror on the substrate is simple and easy.
Easy to do.

According to the third and thirteenth aspects of the present invention, since the coefficient of thermal expansion of the positioning member is equal to or substantially equal to the coefficient of thermal expansion of the dichroic mirror, mechanical stress due to thermal expansion or thermal shrinkage is reduced by the dichroic member. There is almost no occurrence between the mirror and the mirror, and the plane accuracy of the dichroic mirror can be maintained as high as possible.

According to a fourth or a fourteenth aspect of the present invention, one corner of the positioning member is formed at 90 °, the bottom surface thereof is adhered to the substrate, and the dichroic mirror is positioned on the side surface. The bonding of the members and the positioning of the dichroic mirror can be performed simply and accurately.

In the fifth, sixth, fifteenth, and sixteenth aspects, the positioning member is formed of a quadrangular prism member or a triangular prism member, so that the structure is simple, the cost is low, and the positioning of the dichroic mirror is performed. It can be performed easily and with high accuracy.

According to a seventh and a seventeenth aspect of the present invention, since the side faces of the two dichroic mirrors are positioned on both side faces of the positioning member formed of a thick plate-like member, two sheets of the positioning member are used. The dichroic mirror can be positioned, and the number of parts and the number of assembly steps can be reduced.

In the eighth and eighteenth aspects, a quadrangular prism-shaped member,
Since the dichroic mirror is positioned between a positioning member such as a triangular prism member or a thick plate member and a positioning member including a plurality of small projections, the dichroic mirror can be positioned with high accuracy and robustness.

In the ninth and nineteenth aspects, a quadrangular prism-shaped member is provided.
A dichroic mirror is adhered to a side surface of a positioning member such as a triangular prism member or a thick plate member, and a positioning member composed of a plurality of small projections is omitted, so that the number of components and the number of assembly steps can be reduced.

According to a tenth aspect of the present invention, there is provided a substrate on which at least the polarizing beam splitter, the dichroic mirror, and the reflection type light valve are mounted, a plurality of columns mounted on the substrate, and the plurality of columns mounted on the plurality of columns. The top plate is made of a member having the same or almost the same thermal expansion coefficient as that of the dichroic mirror, and at least the dichroic mirror is attached so as to be sandwiched between the substrate and the top plate. Despite being able to support the dichroic mirror with high accuracy and stability by the double-sided structure that supports the upper and lower ends, mechanical expansion and contraction between the dichroic mirror and the substrate, multiple columns and the top plate due to thermal expansion and contraction Almost no stress is generated, and the plane accuracy of the dichroic mirror can be maintained as high as possible. Therefore, a full-color image projected so as to form an image on a screen or the like is hardly affected by thermal expansion or thermal contraction, and the blue light, red light, and green light pixels of the full-color image are removed. It is possible to accurately superimpose images without causing color shift due to pixel-by-pixel shift of a full-color image projected on a screen or the like, and to constantly stably project high-quality images for a long period of time. A high quality projection display device can be realized.

In the eleventh aspect, the lower end of the dichroic mirror is fixed on the substrate, and the upper end is slidably inserted into a groove formed on the lower surface of the top plate. No mechanical stress is applied to the dichroic mirror even if the vertical distance between the table and the top plate changes.

According to a twelfth aspect of the present invention, the vibration-resistant cushioning material for the dichroic mirror is disposed in the groove of the top plate into which the upper end of the dichroic mirror is slidably inserted.
The dichroic mirror is not damaged by the vibration of the projection display device during transportation or the like, and the safety is high.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a first embodiment of a projection display apparatus in which the invention is applied to a projector apparatus.

FIG. 2 is a plan view showing a state where a top plate of FIG. 1 is removed.

FIG. 3 is a longitudinal sectional side view of FIG.

FIG. 4 is a perspective view of a projection-type display apparatus according to a second embodiment in which the invention is applied to a projector apparatus with a top plate removed.

FIG. 5 is a perspective view illustrating a third embodiment of a projection display apparatus in which the invention is applied to a projector apparatus, with a top plate removed;

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is a plan view of a projection type display device according to a fourth embodiment in which the invention is applied to a projector device, with a top plate removed therefrom.

FIG. 8 is a perspective view illustrating a projection display device applied to a conventional projector device.

FIG. 9 is a perspective view illustrating a die-cast frame which is considered to be preferable for implementing a conventional projection display device.

FIG. 10 is a schematic plan view illustrating an optical path of the projection display device of FIG.

[Explanation of symbols]

1 is a projection display device, 2 is a light source, 3 is a polarization beam splitter, 4, 5 is a dichroic mirror, 9, 10, and 11
Is a reflective light valve, 12 is a projection lens, 31 is a substrate, 32 and 33 are columns, 34 is a top plate, 36, 37, and 3
8, 47, and 48 are positioning members, 41 is a groove, and 42 is a cushion material.

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[Procedure amendment]

[Submission date] September 3, 1999 (1999.9.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 10

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Fig. 9

[Correction method] Change

[Correction contents]

FIG. 9 is a schematic plan view illustrating an optical path of the projection display device of FIG.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 10 is a perspective view illustrating a die-cast frame which is considered to be preferable for implementing a conventional projection display device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/31 H04N 9/31 CF term (Reference) 2H048 GA01 GA13 GA23 GA24 GA26 GA51 GA61 2H091 FA05Z FA10Z FA26X FA41Z FC15 FD12 FD15 LA04 LA12 MA07 5C060 GB06 GB10 5G435 AA00 AA04 AA17 BB12 BB16 BB17 CC12 DD02 DD05 EE02 EE04 FF00 FF05 GG01 GG04 GG28 GG41 GG46 HH18

Claims (19)

[Claims] 1. A light source, a polarizing beam splitter for polarizing and separating light emitted from the light source, and at least color-separating light polarized and separated by the polarizing beam splitter into red light, green light and blue light. Two dichroic mirrors, and red light, green light, and blue light, which are color-separated by the dichroic mirror, respectively enter, are modulated into red light, green light, and blue light, respectively, and reflected. And the red, green, and blue image lights modulated and reflected by the three reflective light valves, respectively, are reflected by the dichroic mirror and color-combined. And a projection lens that transmits the image light to a screen or the like after being transmitted through the polarizing beam splitter. Splitter, the projection type display device substrates dichroic mirror and the reflective light valve is placed, characterized in that is constituted by a member having a thermal expansion coefficient identical or nearly identical coefficient of thermal expansion of said dichroic mirror. 2. The projection type display device according to claim 1, wherein a positioning member is adhered to the upper surface of the substrate which has been processed with high precision, and the dichroic mirror is positioned by the positioning member. 3. The projection display device according to claim 2, wherein said positioning member is made of a member having the same or substantially the same coefficient of thermal expansion as said dichroic mirror. 4. An angle between a bottom surface of the positioning member, which has been flattened with high precision, and at least one side surface, which has been processed with high precision, is 90 °. 4. The projection type display device according to claim 3, wherein the dichroic mirror is positioned on the side surface of the dichroic mirror that has been flattened with high precision by bonding to at least one side surface of the positioning member. 5. The projection type display device according to claim 4, wherein said positioning member is constituted by a quadrangular prism-shaped member. 6. A projection type display device according to claim 4, wherein said positioning member is constituted by a triangular prism member. 7. The positioning member comprises a thick plate-like member,
5. The projection type display according to claim 4, wherein the side surfaces of the two thick dichroic mirrors which have been processed with high precision are positioned on both side surfaces of the thick plate member which have been processed with high precision. apparatus. 8. A highly accurate dichroic mirror between a positioning member consisting of the quadrangular prism-shaped member, the triangular prism-shaped member or the thick plate-shaped member and a plurality of small projections bonded to the substrate. 8. The projection type display device according to claim 4, wherein the flattened side surfaces are adhered to each other. 9. A highly accurate planar processing of the dichroic mirror on a side surface of the positioning member made of the quadrangular prism-shaped member, the triangular prism-shaped member, or the thick plate-like member adhered on the substrate. 8. The projection type display device according to claim 4, wherein the formed side surfaces are adhered, and a positioning member including a plurality of small projections is omitted. 10. A light source, a polarizing beam splitter for polarizing and separating light emitted from the light source, and at least a light for polarizing and separating the light separated by the polarizing beam splitter into red light, green light and blue light. Two dichroic mirrors, and red light, green light, and blue light, which are color-separated by the dichroic mirror, respectively enter, are modulated into red light, green light, and blue light, respectively, and reflected. And the red, green, and blue image lights modulated and reflected by the three reflective light valves, respectively, are reflected by the dichroic mirror and color-combined. And a projection lens that transmits the image light to a screen or the like after being transmitted through the polarizing beam splitter. A substrate on which the muscular splitter, the dichroic mirror and the reflection type light valve are mounted, and a top plate mounted in a substantially parallel manner at a predetermined height position on the substrate via a plurality of columns, The substrate, the support and the top plate are made of a member having the same or almost the same coefficient of thermal expansion as the dichroic mirror, and at least the dichroic mirror is sandwiched between the substrate and the top plate. A projection type display device characterized by being attached by mounting. 11. A positioning member adhered to the upper surface of the substrate which has been processed with high precision to position the lower end of the dichroic mirror, and the upper end of the dichroic mirror formed on the lower surface of the top plate so as to be slidable. The projection type display device according to claim 10, further comprising an inserted groove. 12. The projection type display device according to claim 11, wherein a cushion material for vibration resistance of said dichroic mirror is arranged in said groove formed on a lower surface of said top plate. 13. A projection display according to claim 10, wherein said positioning member is made of a member having the same or substantially the same coefficient of thermal expansion as said dichroic mirror. apparatus. 14. The positioning member according to claim 1, wherein said positioning member has a bottom surface which has been planarized with high precision and at least one side surface which has been planarized with high precision is formed at 90 °. 11. The projection display device according to claim 10, wherein a side surface of the lower end of the dichroic mirror, which has been planarized with high precision, is positioned on at least one side surface of the positioning member. 15. The projection type display device according to claim 14, wherein said positioning member is constituted by a quadrangular prism-shaped member. 16. The projection type display device according to claim 14, wherein said positioning member is constituted by a triangular prism member. 17. The positioning member is formed of a thick plate-shaped member, and the lower end of the two dichroic mirrors is precisely flat-faced on both sides of the thick plate-shaped member that has been precisely flattened. The projection type display device according to claim 14, wherein is positioned. 18. A lower end of the dichroic mirror is provided between a positioning member composed of the quadrangular prism-shaped member, the triangular prism-shaped member, or the thick plate-shaped member and a plurality of small projections adhered on the substrate. 18. The projection type display device according to claim 14, wherein the projection type display device is adhered. 19. A positioning member comprising the quadrangular prism-shaped member, the triangular prism-shaped member, or the thick plate-shaped member adhered onto the substrate, and a highly accurate flat surface of a positioning member formed of the dichroic mirror. 18. The projection type display device according to claim 14, wherein a side surface processed is adhered, and a positioning member including a plurality of small projections is omitted.