JPS63247720A - Color image projecting device - Google Patents

Abstract

PURPOSE:To enlarge and project a distinct and well-balanced color image by a simple mechanism, by constituting the titled device so that each of three primary color monochrome liquid crystal panels has mirror paths of the same number before and behind its optical path. CONSTITUTION:A monochrome image is formed in each liquid crystal panel 7, 7' and 7'' of R, B and G, and a white light from a halogen lamp 3 goes into a dichroic mirror group 5''. In the mirror group 5'', R is reflected by a mirror 51, B is reflected by a mirror 52, G is reflected by a total reflection mirror 10, and they are made incident on a dichroic mirror group 5''', respectively. Subsequently, R is reflected by a total reflection mirror 11', B is reflected by a mirror 52', and also, G is reflected by a mirror 53' and condensed, and they are superposed on a screen by a projection lens 8. Also, during this time, the monochrome image is obtained by the liquid crystal panels 7'-7''' in each optical path and colored. The panels 7'-7''' are constituted so that a mirror history passes through two times each before and behind them, respectively.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology separates light from a white light source into the three primary colors of green, blue, and red, transmits and condenses the corresponding black and white images, and projects the light. It belongs to the technical field of color images that are enlarged and projected onto a screen using a lens.

<Summary of the gist> The invention of this application is based on the invention in which a dichroic mirror for the first three primary colors is provided to a white light source such as a 1-gun lamp via a condenser lens, and the dichroic mirror for dispersing the first three primary colors is divided into red, blue: green (hereinafter referred to as red, blue: green). R, B, and G (abbreviated as R, B, and G) are separated into different colors, and then condensed into one axis by a second condensing dichroic mirror,
A liquid crystal panel of a monochrome image forming element is interposed in the optical path between these first and second dichroic mirrors, and the image is enlarged onto a screen by a projection lens installed in front of the second dichroic mirror. This invention relates to a color image projection device that projects an image that is
In particular, each element such as a liquid crystal panel for forming a monochrome image has the same number of reflection and transmission mirror history paths in the front and rear optical paths, so that the luminous intensity and illuminance for each color are made uniform, and is an invention relating to a color image projector in which a second dichroic mirror corresponding to the R dichroic mirror of the first dichroic mirror is made into a cold mirror so that each dichroic mirror does not deteriorate in function. .

<Prior Art> As is well known, television images have rapidly developed as a means of transmitting information that can transmit the most amount of information with the highest degree of precision, and have unexpectedly expanded and spread in both consumer and industrial applications. Therefore, there is a need for a technology to project enlarged images onto a screen that can withstand viewing by individuals or small groups as well as viewing by an unspecified number of people. In projection, for reasons such as the lack of brightness in cathode ray tube televisions, a technology has recently been developed that carries image information on the light that passes through a dichroic mirror and projects it on a screen in an enlarged manner, and is now at a practical stage. ing.

As a matter of course, color images have more information than monochrome images, so research and development is required to expand the projection of color images even when projecting the enlarged images onto a screen. has become a target of

Therefore, when a color image is formed on a single color liquid crystal panel, light from a light source such as a halogen lamp is transmitted through the color image information, and the color image information is projected onto a screen using a projection lens, the color liquid crystal panel becomes a monochrome liquid crystal. Since each pixel is coarse compared to the panel, the projected image on the screen is clear, making it difficult to put it into practical use. Therefore, monochrome liquid crystal panels with fine pixels are set for R, B, and G, and each is powered by a halogen lamp, etc. There is a technology in which the light from a white light source is converted into three primary colors through color filters and then superimposed on a screen through each projection lens to obtain a color image. etc. must be set for each of the three primary colors, which makes the device large-scale and has disadvantages such as difficulty in aligning the optical axes and the possibility of color misalignment. As seen in the invention disclosed in Japanese Patent Application No. 60-23353, a color image projection device with a built-in dichroic mirror has been developed that takes advantage of the dichroic mirror's high reflectance and good light absorption properties. .

That is, such a color image projection apparatus will be briefly explained with reference to FIG. For R, B
The dichroic mirrors 51, 52, and 53 for R, B, and G separate the light into the three primary colors of R, B, and G, and the dichroic mirrors 51 for R, B, and G of the second dichroic mirror group 5' face each other. ', 52', 53' sequentially converge the light onto the -axis, and there are polarizing panels 6 in the front and back between the optical paths of each of the dichroic mirrors of the first dichroic mirror group 5 and the second dichroic mirror 5'. Monochrome liquid crystal panels 7, 7' and 71 for R, B, and G, which are set with . The light is projected onto a screen 9 by a projection lens 8, and a color image is superimposed so that the enlarged and clear color image can be viewed.

<Problems to be solved by the invention> However, as shown in Figure 4, the conventional nuclide technology
Each liquid crystal panel 7.
7' and 7' can be set, but for the optical path of R, the history by one dichroic mirror 51, the history by one time by dichroic mirror 51', and the B
In the optical path of , there are three dichroic mirrors 51.5
For the optical path of G, the history of three dichroic mirrors 51, 52, and 53 and the history of three dichroic mirrors 51', 52', and 53' are used. , the history of the dichroic mirror in each optical path is different, and therefore the luminous intensity and degree of loss in each color optical path are different, and the degree of sharpness and color contrast of the enlarged color image on the screen 9 are different. There were problems in that they were slightly different and insufficient, and adjustments were extremely time-consuming.

Furthermore, since each liquid crystal panel 7.7', 7'' is equipped with a pair of front and rear polarizing panels 6.6, the device is complicated and the cost is high.

Furthermore, since polarizing panels and liquid crystal panels are susceptible to functional changes due to temperature, it is necessary to reduce the temperature inside the device. In order to avoid the heat rise caused by
This increased the number of parts, which had the disadvantage of increasing the problems mentioned above.

Further, as shown in FIG. 4, the distances from the projection lens 8 are made equal in each optical path, and each liquid crystal panel 7.7', 7''
In order to set this, it is necessary to increase the distance between the first dichroic mirror 5 and the second dichroic mirror 5' group, which has the disadvantage of increasing the size of the device.

<Object of the Invention> The object of the invention of this application is to solve the problems of the color image projector based on the above-mentioned prior art, and to solve the problems of the color image projector based on the above-mentioned prior art. It is compact and has a simple mechanism using a monochrome dichroic mirror with fine pixels, and in addition to the heating effect, it also ensures that clear and well-balanced color images are displayed on the screen without loss of light. It is an object of the present invention to provide an excellent color image projecting device that can enlarge and project images, thereby benefiting the field of image technology used in the information industry.

<Means/effects for solving the problem> In order to solve the above-mentioned problem, the structure of the invention of this application, which is summarized in the above-mentioned claims, is to solve the above-mentioned problem. White light from a light source such as a halogen lamp installed in the is incident on the first dichroic mirror group by a reflecting mirror and a condenser lens, R is reflected by the first R dichroic mirror, and transmitted B and white light are reflected by the first R dichroic mirror. The G light is converted to B by the second dichroic mirror.
is reflected and G is transmitted, and the G is reflected by a third total reflection mirror and separated into the three primary colors of R, B, and G, and then the R dichroic mirror of the second dichroic mirror group facing each other , or R is reflected by a cold mirror; in this case, the cold mirror allows infrared rays to pass through and escape to the outside of the device to avoid increasing the temperature inside the device, and the second dichroic mirror reflects and condenses B;
The third dichroic mirror further reflects and condenses the G, and the image forming element such as the liquid crystal panel for R is the first dichroic mirror of the second dichroic mirror group,
Alternatively, an image forming element such as a liquid crystal panel for B may be placed behind the cold mirror, or between the second dichroic mirror of the first dichroic mirror group and the second dichroic mirror of the second dichroic mirror group. In addition, an image forming element such as a liquid crystal panel for G is interposed between the second dichroic mirror and the third dichroic mirror of the first dichroic mirror group, so that the three primary colors of light in each optical path are monochrome. The image information is loaded to form a color image, and a color image for each of the three primary colors is superimposed on a screen from a third dichroic mirror of a second dichroic mirror group via a projection lens to project an enlarged image. Therefore, in each optical path, each monochrome liquid crystal panel goes through mirror history three times before and after it, so the optical path for each of the three primary colors is made equal, and moreover, the average history action of the dichroic mirror makes the light It is designed to project an enlarged color image without loss, brightness, clarity, and color shift, and the mechanism is improved by not attaching polarizing panels to the front and back of each LCD panel, but by providing one on the light source side and one on the projection lens side. To simplify and reduce costs,
It is a technical measure that reduces light loss and enables enlarged projection of bright and clear color images.

<Embodiments - Configuration> Next, embodiments of the invention of this application will be described below based on the drawings. Incidentally, the same parts as those in FIG. 4 will be explained using the same reference numerals.

The embodiment shown in FIG. 1 is a basic embodiment, and a color image projecting device 1' which forms the center of the gist of the invention of this application has a concave reflecting mirror 2 near the actual measurement side of a casing (not shown) and emits white light as a light source. A halogen lamp 3 is provided, an infrared filter 9 is provided between the condenser lenses 4 and 4' in front of the halogen lamp 3, and a polarizing panel 6' is provided.
A first dichroic mirror group 5I is provided via the first dichroic mirror group 5I.

Thus, the second dichroic mirror group 5'' is connected to the light source 3.
Dichroic mirror 51 for R and dichroic mirror 5 for B, which are installed at an angle of 45 degrees from the side.
2, and a total reflection mirror 10 are installed at a design distance as short as possible, and a second dichroic mirror group 51 is provided opposite to this, and each dichroic mirror of the first dichroic mirror group 5'' Corresponding to this, a total reflection mirror 11 for R and a dichroic mirror 52' for B are installed.
, G dichroic mirrors 53' are provided at an angle of 45°, and a polarizing panel 6' is provided in front of the dichroic mirrors 53', and a projection lens 8 is provided in front of the screen 9.
is facing.

Therefore, in the invention of this application, the first dichroic mirror group 5" and the second dichroic mirror group 51"
, and a liquid crystal panel as an image forming element is disposed between them, and the liquid crystal panel 7 for R is located along the optical axis in front of the total reflection mirror 11 of the second dichroic mirror group 5''. The B liquid crystal panel 7' is arranged perpendicularly to the optical axis between the dichroic mirror 52 of the first dichroic mirror group 5'' and the dichroic mirror 52' of the second dichroic mirror group 5'', and The G liquid crystal panel 7'' is disposed in front of the B dichroic mirror 52 of the first dichroic mirror group 5'' at right angles to the optical axis.
They are provided at equal distances from the projection lens 8, respectively.

Note that since the display in FIG. 1 is schematic, mathematical distances are not indicated.

Therefore, the mirror history before and after the optical path of each liquid crystal panel is made equal, and for the R liquid crystal panel 7, the dichroic mirror 51 of the first dichroic mirror group 51, the total reflection mirror 11, Furthermore, the light passes through two history of light transmission and reflection before and after the dichroic mirrors 52' and 53' of the second dichroic mirror group 5N, and in the front part of the B liquid crystal panel 7'. The first dichroic mirror group 5 of
1 dichroic mirror 51, 52, and dichroic mirror 52 of the second dichroic mirror group 51
', 53', and in the G liquid crystal panel 7', the dichroic mirrors 51 and 52 of the first dichroic mirror group 5', the total reflection mirror 10 of the first dichroic mirror group 5'', and the The dichroic mirror 53' of the second dichroic mirror group 51 passes through the dichroic mirror 53' twice, and as a result, the transmission and reflection history of the mirror in each optical path of each liquid crystal panel 7', 7' is transmitted twice. It is evenly balanced.

In this embodiment, the total reflection mirror 10.11 and each dichroic mirror are designed to have the same reflectance, and also have the same light absorption rate.

Therefore, all the condensed lights of each optical path that enter the projection lens 8 have the same luminous intensity.

<Embodiment - Effect> In the above configuration, a monochrome image is formed on each liquid crystal panel 7.7', 7'', and the white light from the halogen lamp 3 is reflected by the total reflection mirror and passes through the condenser lens 4.4. The heat rays are removed by the infrared filter 9, pass through the polarizing panel 6' and enter the first dichroic mirror group 5N, R is reflected by the first dichroic mirror group 5', B and G are transmitted, and the second dichroic mirror group 5N reflects the heat rays. In the mirror 52, B is reflected, G is transmitted and reflected by the total reflection mirror 10, R, B, and G are separated and incident on the second dichroic mirror group 52, and R
is reflected by the total reflection mirror 11, B is reflected by the dichroic mirror 52' and condensed, G is further reflected by the dichroic mirror 53' and condensed, and the projection lens 8 passes through the polarizing panel 6' to the screen. 9.

During this time, in each optical path, the monochrome image information is converted into color by the liquid crystal panels 7, 7', 7M installed perpendicularly to the optical axis, and the projection lens 8 is provided with each R, B
, G are condensed in one axis and projected as superimposed and enlarged color images onto the screen 9 via the polarizing panel 6'.

Therefore, in each optical path, as mentioned above, the corresponding R
The liquid crystal panel 7, the liquid crystal panel 7' of B, and the liquid crystal panel 7'' of G have mirror history twice each before and after, so the reflectance and absorption of light are the same. Since the reflectance is high and the absorption rate is low, the color image enlarged and superimposed on the screen 9 via the projection lens 8 has the same luminous intensity in all three primary colors, so there is no color shift and the contrast is good. Since each liquid crystal panel 7.7', 7' is a monochrome liquid crystal panel, a clear image with fine pixels can be viewed.

The embodiment shown in FIG. 2 is another basic embodiment, in which the infrared filter 9 is not interposed between the condenser lenses 4 and 4 compared to the embodiment shown in FIG. Alternatively, instead of the R-light total reflection mirror 11 of the second dichroic mirror group 51, a cold mirror 11' is provided to transmit infrared rays. This mode also has the function of reflecting R light, and therefore has a small number of parts and can be made compact.

Next, the embodiment shown in FIG. 3 is an embodiment of the basic embodiment shown in FIG. A power converter 13 is provided in the upper corner of the halogen lamp 3, and an electronic drive device 14 for forming a monochrome image is provided in the lower corner of the projection lens 8. The lower side of the first dichroic mirror 51 of the dichroic mirror group 5' and the first cold mirror 11 of the second dichroic mirror group 5''
Ventilation holes 15 and 15' are formed in the upper part of the halogen lamp 3, and a condenser lens 4 and a total reflection mirror 2 are integrally formed in front and behind the halogen lamp 3, making it handy and compact. It is convenient for carrying around, can be made mobile, and can be used outdoors.

It should be noted that the embodiments of the invention of this application are of course not limited to the above-mentioned embodiments. For example, the liquid crystal panel of the original image forming element may include a monochrome film for slides, and a cooling device may be attached to the liquid crystal panel. Various aspects such as the above can be adopted.

<Effects of the Invention> As described above, according to the invention of this application, basically a monochrome image of the original image is formed on an image forming element such as a monochrome liquid crystal panel, and white light from a light source such as a halogen lamp is transmitted to the first dichroic mirror. When the light is separated into R, B, and G by the group, focused by the second dichroic mirror group, and superimposed and projected onto the screen by the projection lens, each monochrome liquid crystal panel is divided into R, B, and G by the first and second dichroic mirror groups, and By making the mirror history of light transmission and reflection the same before and after each optical path in the dichroic mirror group, the reflection and absorption of light in each optical path is the same, so that the light is focused on the - axis and colored. Light with image information has the same luminosity for each of the three primary colors, so
There is no color shift in the enlarged color image superimposed on the screen, and the excellent effect is that you can enjoy clear images due to the fineness of the pixels of each monochrome LCD panel at the brightness specified by the setting. is conquered by Qin.

Dichroic mirrors and total reflection cold mirrors have low light absorption and high reflectance, resulting in low light loss, high light energy efficiency, and low cooling running costs. be done.

Further, by uniaxial light condensing using a dichroic mirror, a clear color dichroic mirror without deviation can be obtained.

[Brief explanation of the drawing]

1 to 3 are detailed explanatory views of the invention of this application, in which FIG. 1 is a schematic diagram of the basic aspect of one embodiment, FIG. 2 is a schematic diagram of the basic aspect of another embodiment, and FIG. 3 is a schematic diagram of the basic aspect of another embodiment. 4 is a cross-sectional side view of a stationary embodiment, and FIG. 4 is a schematic diagram of a color image projection apparatus based on the prior art. 3... White light source, 5'... First dichroic mirror group, 5"...
second dichroic mirror group, 7... liquid crystal panel;
8... Projection lens, 11'... Cold mirror

Claims (2)

[Claims] (1) Three image forming elements of red, green, and blue are installed between the first dichroic mirror group for dispersing the three primary colors installed in front of the white light source and the second dichroic mirror group for condensing light installed in front of it. In a color image projector in which a projection lens is provided in front of a second dichroic mirror group, each of the image forming elements has the same number of mirror paths before and after its optical path. Characteristic color image projection device. (2) Three image forming elements of red, green, and blue are installed between the first dichroic mirror group for dispersing the three primary colors installed in front of the white light source and the second dichroic mirror group for condensing light installed in front of it. In the color image projector, in which a projection lens is provided in front of a second dichroic mirror group, each of the image forming elements has the same number of mirror paths before and after its optical path, and A color image projection device characterized in that a mirror in a second dichroic mirror group corresponding to a red dichroic mirror in the first dichroic mirror group is a cold mirror.