JPH0812343B2 - Image projection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The disclosed technology relates to an optical system of an apparatus for enlarging and projecting a monochrome image formed on an original image panel such as a liquid crystal panel on a wall surface or a screen as a color image on a screen. Belongs to the technical field of construction.

<Summary of summary> Therefore, the present invention is configured so that light from a light source such as a halogen lamp provided at the lower side of the screen with respect to the screen provided at the front is incident on the front surface of the dichroic prism provided at the rear of the projection lens. After being reflected and transmitted into red (R), green (G), and blue (B) by the light transmitting / reflecting surface in the dichroic prism, and after being incident on and reflected by original image panels such as monochrome type liquid crystal panels. , An invention relating to an image projection device for projecting a color image by enlarging it on a screen by a projection lens, and in particular, having a non-perpendicular light transmission reflection inside a dichroic prism, and red ( R), green (G), blue (B) monochrome liquid crystal panels and other reflective original image panels are directly attached, and the front surface is parallel to the dichroic prism. The present invention relates to an image projection device that allows incident light rays to be incident, is compact, has high brightness, is free from displacement of each optical mechanism portion, and can improve contrast.

<Prior art> As is well known, in modern society, whether in industrial society or civil society, there is a sudden transition from the physical society to the information society, and information processing such as information transmission becomes extremely important. Due to the rapid research and development of electron optics, information processing and transmission by images are being used in all fields. The mass transmission mode with the improvement of usability is polarized and it is developing momentarily while making the most of each advantage.

On the other hand, due to the development of liquid crystal panels and the like, the method of utilizing the light transmittance of the original image panel such as the liquid crystal panel and projecting the original image panel image on the screen in a magnified manner and transmitting the information to a large number of viewers is simply entertainment and education. Not only information transmission,
It is beginning to play an important role in transmitting industrial information and research information.

Such information processing by the image projection method is often influenced by the accuracy of the image projection apparatus, and in particular, since the mode of enlarging and projecting on the screen via the projection lens is adopted, each optical element in the apparatus frame is The positional deviation of the mechanical portion extremely affects the image accuracy, and has a great negative effect on the brightness and brightness.

For example, as shown in FIG. 13, in order to project a magnified image on the screen 2 by the image projection device 1, the device frame 3
As a red (R), green (G), and blue (B) original image panel provided at a predetermined portion in the liquid crystal panel 4, 4 ′, 4 ″, a monochrome image device is formed through a predetermined electronic drive device 5. Then, from the light source 6 such as a halogen lamp, the reflection mirror 8,
8 ', projection lens 10 through dichroic mirror 9,9,9,9
There is a technique for projecting a color image by synthesizing.

<Problems to be Solved by the Invention> As described above, in the seed image projection apparatus 1, the liquid crystal panels 4, 4 ', 4 "and the reflection mirrors 8, 4", 8 ′ and dichroic mirrors 9, 9 ... are extremely difficult to center and require a high level of skill. In addition, maintenance and inspection are extremely troublesome, and in addition, alignment is extremely operational. In addition to the difficult points, the optical path is long and the device is large, so it cannot be made compact and it is difficult to handle.

<Object of the Invention> An object of the present invention is an apparatus for enlarging and projecting an image formed on a liquid crystal panel or the like onto a screen or the like via a projection lens, which is involved in a system of the recent related art which is extremely important for information transmission processing. The technical problem that should be solved is
Compact and convenient to carry around, it can be installed freely, and maintenance, inspection, and maintenance can be performed smoothly, and it is easy to assemble and adjust each optical mechanism, maintain high brightness, and maintain sufficient brightness. It aims to provide an excellent image projection device that is useful for the field of application of image processing technology in the information industry by holding it, obtaining good contrast, and enlarging and projecting high-definition color images on the screen. It is a thing.

<Means and Actions for Solving the Problems> In order to solve the above-mentioned problems, the structure of the present invention, which has the above-mentioned object, is formed on an original image panel such as a liquid crystal panel in order to solve the above-mentioned problems. When a projected image is enlarged and projected on the screen through a projection lens to obtain a color image, etc., incident light from a light source such as a halogen lamp provided at the lower front side is incident on the front surface of the dichroic prism provided in the device frame. The reflected light from the surface is removed from the projected light on the screen by entering the light-transmitting inclined reflection plate, etc., and further, it is made into parallel rays by the condenser lens and enters into the dichroic prism and enters the inside. Red (R), blue (B) due to the light transmission and reflection surface of
Is reflected and transmitted to a monochrome liquid crystal panel as an original image panel attached to both sides, and then reflected by a mirror to take a reverse optical path.

Then, since the reflecting surfaces of the dichroic prism intersect at non-perpendicular, the incident light is reflected by both the reflecting surfaces of red (R) and blue (B), and the light of green (G) component is forwarded. It prevents the light from going back and mixing in the projection light, and the straight green (G) component is incident on the liquid crystal panel as a monochrome original image panel for green (G) and is reflected by the rear mirror. The surface is covered with a filler such as ethylene glycol to prevent surface reflection and contribute to contrast improvement.The reflection mirror connected to the back surface of each original panel is a large cooling surface area such as a copper plate. By being cooled by the member, the temperature rise of the original image panel is prevented and the deterioration of the image holding function is prevented, and the light emitted from the dichroic prism is projected on the screen at a predetermined magnification by the projection lens. Over image or the like is high luminance, and, as can be visually recognized with good contrast in sufficient brightness, and red (R), blue (B) is a strong reflection characteristic S
Polarized and green (G) incident light is P-polarized light with strong transmission characteristics, or all (R), (G), and (B) have a unified polarization direction to impart an invisible function of the image. It is a technical measure that makes it possible.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS.

It should be noted that parts that are the same as those in FIG. 13 will be described using the same reference numerals.

In the embodiment shown in FIGS. 1 to 3, reference numeral 1'is an image projecting device which is one of the main features of the present invention, and in the illustrated mode, it shows a main optical mechanism portion, which is not shown in the drawings. It is designed to be installed in a device frame made of plastic or the like, a projection lens 10 is provided so as to face a front screen (not shown), and a crossing surface 12 of a light transmission incidence surface near the inner center of the device frame, A dichroic prism 81 having non-perpendicular 12 'has a light-transmitting inclined plate 83 on its front surface, is provided below the projection lens 10, and is equipped with a reflector 6 and a condenser lens 7', such as a halogen lamp. Condenser lens for incident ray 13 from the light source 3
80 is provided in advance, so that the inclined plate 83 prevents the surface reflected light rays from entering the incident light rays 13 ′ on the projection lens 10 side, and both sides of the dichroic prism 81, and
Monochrome liquid crystal panels 41, 41 ', 41 "are directly attached to the rear surface as insert picture panels through insert prisms 82, 882, 82, and an appropriate reflection mirror 11 is provided on the rear surface thereof.
Are also provided, and further, cooling panels 15 such as copper plates are provided on the rear surface thereof so that the image forming functions of the liquid crystal panels 41, 41 ', 41 "are not deteriorated.

As shown in FIG. 3, each monochrome liquid crystal panel
In 41, 41 ′ and 41 ″, polarizing plates 45 and 45 are provided on the inner liquid crystal 42 via glass substrates 43 and 43 on both sides of the liquid crystal 42, but the insert prism 82 and the reflection mirror 11 are provided. At the boundary of the light transmitting material 45 such as ethylene glycol.
Is provided to prevent surface reflection of light and improve contrast.

The function of the above-mentioned structure will be described with reference to FIG. 4 and the following theoretical drawings. As shown in FIG. 4, the liquid crystal panels 41, 41 ', 41 "are insert prisms 82, 82, 82" as monochrome primary image panels of three primary colors. The dichroic prism 81 is fixed to the dichroic prism 81 with an epoxy adhesive or the like through the inclined plate.
There is no deviation with respect to 83, etc., there is no need for position adjustment in initial assembly and maintenance, and the incident path 13 and
The optical path of the reflection path 13 'can be the shortest distance, and the device can be made compact and compact.

Further, as shown in FIG. 5a, since the light-transmitting inclined plate 83 is provided on the front surface of the dichroic prism 81, the surface reflected light 13 ″ of the incident light 13 is changed to the conventional mode shown in FIG. 5b. Light emitted from the dichroic prism 81 as
By returning to the light source side without being mixed into 3 ', the surface reflected light can be removed and the contrast is improved.

Further, as shown in FIG. 6a, the insert prism 82 and the reflection mirror 15 are provided with a light-transmissive filling material 45 such as ethylene glycol at a boundary portion between the surfaces, thereby forming a surface at the boundary surface. There is no risk of reflection being prevented and surface reflection 13 ″ as shown in FIG. 6b being prevented and being mixed into the regular reflected light 13 ′.

This is also an effect of preventing surface reflection due to a change in the refractive index due to the inclusion of the air layer 14 at the boundary surface shown in FIG. 6b.

Thus, as shown in FIG. 7a, in the present invention, the dichroic prism 81 has the light transmitting / reflecting surfaces 12, 12 'of the seventh embodiment.
Since it is not a conventional right-angled crossing as shown in FIG. b but a non-right angle set crossing state, the red (R) anti-slope 12 and the blue (B) reflecting surface 12 'are formed. In order to be able to remove the reflected light 13 of the green (G) component, the projection lens for the reflected light 13 of the green (G) as in the conventional mode as shown in FIG. 7b.
Mixing on the 10 side can be prevented, and clear color images can be obtained.

By the way, as shown in FIG. 8, the red (R) and blue (B) reflected light components on the reflecting surfaces 12 and 12 'in the dichroic prism 81 have strong S-polarized components. On the other hand, since the transmitted light (G) has a strong P polarization component, if the polarization properties of the liquid crystal panels 41, 41 ', 41 "are adjusted to this, a light loss is reduced and a bright image can be obtained.

Thus, in general, a polarizing panel of a liquid crystal panel has a loss of light because it does not particularly define these polarizability, whereas in the present invention, red (R), and
The polarization panel 44 of the blue (B) liquid crystal panels 41 and 41 'has a strong S polarization component, and the green (G) polarization panel 44 of the transmitted light has a strong P polarization component. As shown in the figure, red (R), blue (B), and green (G) images with no light loss for reflected light and transmitted light are obtained.

Thus, as shown in FIG. 9, a dichroic prism
By setting the condenser lens 80 in front of the inclined panel 83 attached to the front surface of the 81 for a predetermined distance toward the screen, the dichroic prism 81 and the liquid crystal panels 41, 41 ', 4 are arranged.
It is possible to irradiate incident light 13 ', which is almost perpendicular to 1 ",
Each of them is capable of fully exerting a predetermined function.

Therefore, in the case where the condenser lens 80 is not provided, incident light enters the dichroic prism 81 and the liquid crystal panels 41, 41 ', 41 "obliquely, and there is a demerit that the characteristics of the liquid crystal panel cannot be fully exhibited. can avoid.

Further, the embodiment shown in FIG. 10 is a mode in which the polarization direction of the outgoing light with respect to the projection lens 10 is unified in the same direction so as to improve the optical characteristics. The red (R) and blue (B) polarization directions that are reflected once are S-
On the other hand, the polarization direction of green (G), which is reflected once, is set to S + 45 degrees, and the polarization of all outgoing light is set to S + 45 degrees.
In order to unify the polarization direction, improve the light characteristics, and form an invisible image that is visible only to the person wearing polarized glasses.

And, the embodiment shown in FIG. 11 has liquid crystal panels 41, 41 ',
In order to prevent the temperature rise in order to maintain good 41 ″ image characteristics, a cooling material 11, 11, 11 made of copper plate or the like is additionally provided on the back surface of each of the cooling plates 11. A large number of thin fins 11 ', 11' ... Are planted on the rear surface so that the image forming function can be improved.

Further, the embodiment shown in FIG. 12 has liquid crystal panels 41, 41 ', 41 "
This is a mode in which color filters 15, 15, 15 are attached to the front surface of the device to improve the image color characteristics.

The embodiment of the present invention is not limited to the above-mentioned embodiments, and various original modes such as another slide film can be used for the liquid crystal panel as the original image panel.

<Effects of the Invention> As described above, according to the present invention, basically, an image formed on an original image panel such as a small liquid crystal panel is made to transmit light from a light source such as a halogen lamp and is enlarged and projected on a screen by a projection lens. In the device, the optical path in the device frame can be improved by directly attaching the monochrome original image panels such as three liquid crystal panels to the both side surfaces and the rear surface of the dichroic prism and adopting the front incidence front reflection method. It is extremely short and the device is compact and compact,
Moreover, there is no need for alignment or centering of the liquid crystal panel, etc., and the entire device is made into a kind of solid state with good durability, and at the same time, the performance as originally designed was always fully exerted, and the contrast was high. The excellent effect that a bright image with brightness can be obtained is exhibited.

Then, the maximum efficiency by using the dichroic prism is fully utilized, and there is an effect that the brightness and luminance of the image can be increased.

Furthermore, by providing a light-transmitting inclined reflection plate on the front surface of the dichroic prism, it is possible to prevent front surface reflected light from entering the screen and obtain a bright and clear color image or the like.

Also, by interposing a filling material such as a light-transmitting material on the boundary surface of the internal optical parts, the surface reflection at the boundary surface is prevented, and the surface reflection due to the difference in refractive index at the boundary surface is also prevented. As a result, the contrast can be improved.

Further, by making the light transmitting / reflecting cross surface in the dichroic prism non-perpendicular, it is possible to remove the reflected light of the green (G) component mixed in the red (R) and blue (B) reflecting surfaces,
There is an effect that an image with a clear color tone can be obtained.

Thus, when liquid crystal attached to the side surface of the light transmitting / reflecting surface of the dichroic prism and the rear surface is used as an original image panel, the polarizing panel for red and blue original images is used for S-polarization, and the rear panel is used. For the green original image panel, the polarizing panel is used for P-polarized light, so that it is possible to obtain a bright image by reducing the loss of light by utilizing the reflection and transmission characteristics of light. To be done.

In addition, by adding a color filter to the original image panel, it is possible to perform adjustment that cannot be adjusted with the dichroic prism.

[Brief description of drawings]

1 to 12 are explanatory views of an embodiment of the present invention.
FIG. 4 is an enlarged plan view of a basic embodiment, FIG. 2 is a side view of the same, FIG. 3 is an enlarged sectional view of an A portion of FIG. 2, and FIGS. 4 to 12 are detailed sectional views of respective mechanism portions. Fig. 5 is a cross-sectional view of the basic optical mechanism, Fig. 5a is a cross-sectional view of the inclined plate with a dichroic prism, Fig. 5b is a cross-sectional view of the prior art in contrast to Fig. 5a, and Fig. 6a is an interface antireflection mechanism. 6b is a sectional view of the prior art in comparison with FIG. 6b, FIG. 7a is a sectional view of the non-perpendicular light-reflecting surface of the dichroic prism, and FIG. 7b is a sectional view of the light-reflecting surface of the mechanical arrangement based on the prior art. Fig. 8 is a plane sectional view of polarized light of red (R), blue (B), and green (G), Fig. 9 is a plane sectional view of an arrangement of condenser lenses, and Fig. 10 is a longitudinal sectional view of a polarized light path. FIG. 11 is a plan sectional view of an arrangement of cooling materials for a liquid crystal panel, FIG. 12 is a schematic plan sectional view with a color filter attached, and FIG. 13 is a schematic view of an image projection apparatus based on the prior art. An expression sectional view. 1 '... Image projection, 2 ... Screen 10 ... Projection lens, 12, 12' ... Light transmitting / reflecting surface 13 ... Front incident light, 13 '... Front reflected light 41, 41', 41 ". Original image panel, 45 …… Light transmitting material 80 …… Condensing lens, 81 …… Dichroic prism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Sakurai 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Kobe factory (56) Reference JP-A-63-292187 (JP, A) )

Claims (1)

[Claims] 1. A front-incidence front-reflective image projection device in which a dichroic prism, which is disposed through a projection lens with respect to a lower light source and a screen provided in front, is additionally provided with a reflective original image panel. A dichroic prism having a light transmitting / reflecting surface is attached to three surfaces of three monochrome original image panels for red, green, and blue, and a light-transmitting inclined reflection plate is attached to the front surface of the dichroic prism. An image projection device characterized by being provided.