JPH0335285A - Display device - Google Patents

Abstract

PURPOSE:To obtain an image whose colors are well-balanced by interposing a transparent body for controlling the extent of the luminous flux of image light in an optical path whose length are longer than other optical pathes between respective display parts and an image light synthesizing element. CONSTITUTION:The transparent bodies 12 and 12 are respectively interposed in the optical path of red image light AR from a red image display part 11R and in the optical path of a blue image light AB from a blue image display part 11B having respectively long optical pathes and provided with reflection increasing mirrors 7 and 7 among respective optical pathes between respective display part 11R, 11G and 11B and the image light synthesizing element 6 so that the extent of the luminous flux of the red image light AR and the blue image light AB may be controlled. Thus, the image light with respective colors from respective display parts is made incident on the image light synthesizing element in the state of having nearly equal brightness, so that the image whose colors are well-balanced is obtained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to displaying images of a plurality of colors on a plurality of display sections to create a full-color image, and displaying images of each color from each display section. The present invention relates to a display device that synthesizes light using an image light synthesis element to produce the full-color image.

[Conventional technology]

For example, some display devices such as projectors are designed to display images of multiple colors on multiple display sections to create a full-color image.

Fig. 5 and Fig. 6 respectively show conventionally known display devices of this type, which are equipped with three liquid crystal display sections and display a red image and a green image to create a full-color image. This is a liquid crystal projector that displays a blue image on the three liquid crystal display sections mentioned above, and projects and displays a full-color image on a screen by combining the three-color image light of red, green, and blue from each display section. There is.

First, the liquid crystal projector shown in FIG. 5 will be explained. In the figure, IR, IG, and la are three liquid crystal display sections. Each of the liquid crystal display sections 'Rl 1 c *18 is composed of a liquid crystal display panel having the same structure, and the liquid crystal display sections IR, IG, and 1B are arranged side by side on the same plane. These liquid crystal display parts IR, IO, ig
are driven to display in synchronization, the first liquid crystal display part IR is a red image display part, the second liquid crystal display part IG is a green image display part, and the third liquid crystal display part IB is a red image display part. It is a blue image display section. Reference numeral 2 denotes a light source, and the light source 2 includes a light source lamp 2a and a reflector 2b that reflects the emitted light from the light source lamp 2a as parallel rays. In front of this light R2, there is a red light separation dichroic mirror 3R that reflects red component wavelength light and transmits other wavelength light, and a green light separation mirror 3R that reflects green component wavelength light and transmits other wavelength light. A dichroic mirror 36 for blue light and a dichroic mirror 3B for separating blue light that reflects blue component wavelength light and transmits other wavelength light are arranged in order at an inclination angle of 45''.

These dichroic mirrors 3R.

3c and 3s are the respective liquid crystal display portions IR.

The red light R of the white light from the light source 2 is reflected by the red light separation dichroic mirror 3R and enters the red image display section IR.
Light transmitted through dichroic mirror 3R for red light separation (
Of the green and blue lights), the green light G is reflected by the green light separation dichroic mirror 3G and is displayed on the green image display section IG.
The blue light B that is incident on the dichroic mirror 36 for separating green light passes through the dichroic mirror 36 for separating blue light.
The light is reflected by the blue light and enters the blue image display section IB. Also, 4a, 4b.

4C is three projection lenses arranged on the output side of each of the liquid crystal display sections IR, 10, 1B, and the light transmitted through each of the liquid crystal display sections IR, 10, la, that is, each liquid crystal display section 1jl+IG, 1B. Red, green from.

The three-color blue image lights AR, AG, and AB are enlarged and projected onto a screen 5 by projection lenses 4a, 4b, and 4c, respectively, and are superimposed on the screen 5 to be combined into one full-color image. .

Furthermore, the liquid crystal projector shown in FIG. 6 displays red and green signals from three liquid crystal display sections IR, lc, and IB.

The three-color blue image light AR+AG+AB is combined into one full-color image light ARGB by the image light combining element 6 and then projected onto the screen 5. This liquid crystal projector also has three liquid crystal display sections IR, la, la and the light source section have the same configuration as the liquid crystal projector shown in FIG. The image light combining element 6 is a dichroic prism in which four triangular prisms are bonded together and a dichroic coating is applied to the bonded surfaces. Boundary surface (right side in the figure)
The entrance side boundary surface facing the three liquid crystal display parts IR,1
It is arranged to face the central green image display section 1G of 0 and is. In addition, in front of the other two incident-side boundary surfaces of the image light combining element 6, an image light combining element is provided which transmits the red image light AR from the red image display section IR and the blue image light As from the blue image display section IB, respectively. An intensifying mirror 7.7 for reflecting the light toward the image beam 6 is arranged at an angle of inclination of approximately 45°, and one projection lens 4 is arranged on the output side of the image light combining element 6.

That is, this liquid crystal projector separates the white light from the light source 2 into red, green, and blue lights R, G, and B by each dichroic mirror 3R and 30° 3B, and separates the white light from the light source 2 into red, green, and blue lights R, G, and B. , B are incident on each liquid crystal display section IR, IG, 1B, respectively, and each liquid crystal display section IR+10
．． Red and green from 1B.

The blue image lights AR, A□, and AB are incident on the image light combining element 6, and the three-color image lights AR, Ac, and Aa are combined into one full-color image light AR, B by the image light combining element 6.
The full-color image light ARGB emitted from the image light combining element 6 is enlarged and projected onto the screen 5 by the projection lens 4.

[Problem to be solved by the invention]

However, in the conventional display device (liquid crystal projector) shown in FIG. 5, each liquid crystal display section IR.

Red, green, and blue image lights AR and AG from lc and la.

AB is projected onto the screen 5 by projection lenses 4a, 4b, and 4c, respectively, and each image light AH is generated.

Since Aa and Aa are superimposed on five screens to synthesize one full-color image, three projection lenses 4a, 4b, and 4c are required, which makes the display device expensive, and each projection lens Even if the optical axes of 4a, 4b, and 4c are aligned on the 5th screen surface, each image light AR, AC, and AB projected onto the 5th screen surface is shifted due to the lens aberration of each projection lens 4a, 4b, and 4c. Another drawback is that the full-color image that is synthesized on five screens has poor image quality at the outer periphery.

On the other hand, the display device (liquid crystal projector) shown in FIG. 6 combines red, green, and blue image lights AR, AG, and AB from each liquid crystal display section IR, IG, and 1B into one full-color image using an image light combining element 6. Since the light A is combined with Ra1l and then projected onto the screen 5, only one projection lens 4 is required, and the image light combining element 6 is cheaper than lenses, so the price of the display device can be reduced. can be done,
In addition, full-color image light A, which is a combination of red, green, and blue image lights AR, Aa, and AH, is transmitted through one projection lens 4.
Since the image is projected onto the screen 5, there is no problem of image quality deterioration due to lens aberration.

However, in the conventional display device shown in FIG.
a and the image light combining element 6, and the other liquid crystal display section facing the image light combining element 6 via the mirror 7 (
(Red image display section and blue image display section) Since there is a difference in the optical path length between IR, Ill and the image light combining element 6, the red and blue light entering the image light combining element 6 through the long optical path. The spread of the luminous flux of the image light A R+ A B is large, and the brightness of the red and blue image light A R+ A B is attenuated, so that the full color image light A Ra synthesized in the image light combining element 6 becomes , the problem was that the red and blue components were weak, resulting in an image with poor color balance.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to distribute images of multiple colors to multiple display sections arranged on the same plane to create a full-color image. The image light of each color from each display section is synthesized by an image light synthesis element to form the full color image, and the full color image synthesized by the image light synthesis element is made into an image with good color balance. The objective is to provide a display device that can perform

[Means to solve the problem]

The projection display device of the present invention divides and displays images of a plurality of colors to create a full-color image on a plurality of display sections arranged on the same plane, and uses image light of each color from each of the display sections to display images of a plurality of colors to create a full-color image. In a display device that synthesizes the full-color image using a photosynthesizing element, the spread of the luminous flux of the image light is restricted to at least a longer optical path among the optical paths between each of the display sections and the image photosynthesizing element. It is characterized by having a transparent body interposed therebetween.

[For production]

In other words, the display device of the present invention is capable of reducing the spread of the luminous flux of the image light that enters the image light combining element through at least a long optical path among the image light of each color that enters the image light combining element from each display section. is regulated by the transparent body to make the spread of the luminous flux of each color of image light incident on the image light combining element from each display section almost the same. Since the image light of each color can be incident on the image light combining element in a state in which the optical path lengths are approximately equal, that is, in a state in which the brightness is approximately equal, the full color image synthesized by the image light combining element can be created with good color balance. It can be an image.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3, taking a liquid crystal projector as an example.

FIG. 1 shows the overall configuration of a liquid crystal projector.

In FIG. 1, parts having the same configuration as the liquid crystal projector shown in FIG. 6 are denoted by the same reference numerals, and the explanation thereof will be omitted.

The liquid crystal projector of this embodiment has three display sections 11R and 1 that display a red image, a green image, and a blue image, respectively.
1c and 11a are arranged in a row on the same plane, and the white light from the light source 2 is transmitted to the dichroic mirrors 3R and 3.
Separate into red, green, and blue light R, G, and B by a and 3a,
The red, green, and blue lights R, G, and B are incident on each product display section 11R2liG, lla, and the three-color image light AR+ of red, green, and blue from each display section 11R, 11c, and 11a is input. AG + AB is made incident on an image light combining element 6 consisting of a dichroic prism in which four triangular prisms are bonded together and a dichroic coating is applied to the bonded surfaces, and the light is synthesized into one full-color image light A RGB. Image light A RGB is projected onto the screen 5 by the projection lens 4, and each display section 11R, 11
a, 1 is formed on one liquid crystal display panel 10.

FIG. 3 shows the three display sections 11R and IIG.

This shows the liquid crystal display panel 10 in which 11B is formed.
The central part of this liquid crystal display panel 10 is a green image display section 11.
c, and both ends are a red image display section 11R and a blue image display section 11a, respectively. And each of these display sections 11R, 11a.

11g, a large number of striped transparent signal electrodes (common electrodes) X+, X2, ...Xn along the length direction of the liquid crystal display panel 10, and the scanning electrodes XI,
X2. ...Many striped transparent signal electrodes (segment electrodes) perpendicular to Xn Y l.

Y2. ... Yn is formed. Note that the scanning electrodes X, , X2 . ...Xn is formed on one side of a pair of transparent substrates facing each other with a liquid crystal layer in between, and the signal electrodes Yl, Y
2. ...Yn is formed on the other transparent substrate. And each display section 11R, IIG.

118 scanning electrodes X, , X2. ...
Y, . . . Yn are independent electrodes for each display section, and each display section 1 . IR, IIG.

11B, the scanning electrodes X, , X2 . . . . A scanning voltage is sequentially applied to Xn, and each display section 11R, 11a.

11a signal electrodes Y,, Y2. ...The display is driven by applying red, green, and blue image signals to Yn, respectively. Although a simple matrix type liquid crystal display panel is shown here, the liquid crystal display panel 10 may be of a TPT active matrix type in which each pixel electrode is selectively driven by a thin film transistor (TPT).

As shown in FIG. 1, the liquid crystal display panel 10 has a central green image display section 11a located on the incident side opposite to the output side boundary surface of the three incident side boundary surfaces of the image light combining element 6. The red image display section 11R and the blue image display section 11B on both end sides are connected to the image light combining element 6, facing the boundary surface.
The mirror 7.7 is disposed opposite to an intensifying mirror 7.7 which is disposed at an angle of inclination of approximately 45 m so as to face the other two entrance-side boundary surfaces of the mirror 7.7.

Further, in FIG. 1, reference numeral 12.12 indicates each display section 11R, llc of the liquid crystal display panel 10.

Among the optical paths between 11g and the image light combining element 6, a longer optical path including the amplifying/reversing mirror 7, that is, an optical path of the red image light AR from the red image display section 11R, and a blue image display section 11B. These are transparent bodies that are interposed in the optical path of the blue image light AB from and regulate the spread of the luminous fluxes of the red image light AI and the blue image light A, respectively. This transparent body 12
．． 12 is made of glass or the like with high light transmittance. The incident side boundary surface of the transparent body 12.12 facing the red image display section 11R and the blue image display section 11a is a plane parallel to the surface of the liquid crystal display panel 10, and the image light combining element 6
The output side boundary surface facing the image light combining element 6 is a plane parallel to the input side boundary surface of the image light combining element 6. Also, this transparent body 1
The surface facing the amplifying mirror 7 in 2.12 is an inclined surface inclined at an angle of approximately 45° with respect to the entrance side boundary surface and the exit side boundary surface of this transparent body 12, 7 is placed in contact with this inclined surface.

In this embodiment, an amplifying and opposing mirror 7 is arranged on the inclined surface of the transparent body 12, but this amplifying and opposing mirror 7 is
The transparent member 12 may be formed by applying an anti-proliferation coating to the inclined surface thereof.

Therefore, in the liquid crystal projector of this embodiment, each display portion 11R, 11° of the liquid crystal display panel 10.

Among the optical paths between 11a and the image light combining element 6, a spread of the luminous flux of the red image light R and the blue image light AII is applied to the optical path of the red image light A, which has a long path length, and the optical path of the blue image light AH. Because there is a transparent body 12.12 that regulates the
Each display section 11R, 11c of the liquid crystal display panel 10,
Image light AR of each color of red, green, and blue enters the image light combining element 6 from 11a.

It is possible to make the spreads of the light beams of Ac and Aa almost the same.

That is, FIG. 2 shows the effect of regulating the spread of the light beam by the transparent body 12, and shows the effect of the transparent body 12 from the point P on the optical axis O to the transparent body 1.
The light incident on the transparent body 12 is refracted as shown in the figure and enters the transparent body 12, and is refracted and emitted from the transparent body 12 as shown in the figure. It can be regarded as light from point P'. In other words, when looking at the object at point P through the transparent body 12, this object is at point PP
The distance ML appears to be shifted toward the front by the distance ML between ', and the distance ML is L-, where n is the optical refractive index of the transparent body 12, and g is the length of the transparent body 12 along the light transmission direction. (1-1/n)iJ.

A virtual image A of the red image light AR and the blue image light A8 entering the image light combining element 6 through the transparent body 12.12.
RAll' (see FIG. 1) is the optical path length between the green image display section 11G and the image light combining element 6 and the red image display section 11.
The red image display section 1 is moved by a distance corresponding to the difference in optical path length between the R and blue image display section 11B and the image light combining element 6.
1R and the front of the blue image display section 11a, the refractive index n of the transparent body 12.12 and the transparent body 12
．． If the length along the light transmission direction of 12 (the length from the incident side boundary surface to the amplifying and opposing mirror 7 surface, the length from the reflecting mirror 7 surface to the emitting side boundary surface) g is selected, the above virtual image ARA
The apparent upper optical path lengths of red image light A and blue image light AB, which can be regarded as light from position B, and green image light AC from green image display section 11c are approximately equal.

Therefore, according to the liquid crystal projector, each color of image light A from each display section 11R, 11c, 11B
Since R+ A G r A B can be made to enter the image light combining element 6 in a state where the spread of the luminous flux is almost equal, that is, in a state where the brightness is almost equal, the color balance of the full color image light ARGB synthesized by the image light combining element is This full-color image light A ROB can be projected onto the screen 5 as a good image.

In the above embodiments, a liquid crystal projector has been described, but the present invention is not limited to liquid crystal projectors, but can also be applied to, for example, a viewfinder of a video camera.

FIG. 4 shows a second embodiment of the present invention, and this embodiment is an example in which the present invention is applied to a viewfinder.

In FIG. 4, reference numeral 13 indicates a case of a video camera, and reference numeral 14 indicates a case of a viewfinder.A lens barrel 16 equipped with an eyepiece lens 15 is provided on an end surface of the case 14. Note that 17 is an eyecup provided at the end of the lens barrel 16. Inside the case 14, there is a liquid crystal display panel 10 on which red, green, and blue image display sections 11*, 11c, and 11s are formed, an image light combining element 6 made of a dichroic prism, and an amplifying/reversing mirror 7.7. , transparent bodies 12 and 12 for regulating the spread of the luminous fluxes of the red image light 8 and the blue image light A are provided in the same arrangement as in the first embodiment, and further behind the liquid crystal display panel 10. are each image display section 11R of this liquid crystal display panel 10,
11c and 11a respectively, red, green,
Light source that emits blue light (panel light source using fluorescent lamps)
18R, 18c.

18! I is placed.

This viewfinder has each light source 18R18a, 18a
The red, green, and blue light from the liquid crystal display panel 10 is transmitted to each image display section 11R, llc.

111+, and these display sections 11R, 11c.

Three-color image light of red, green, and blue from 11a ARlA C*
A and B are incident on the image light combining element 6 and combined into one full color image light A 118, and this full color image light A ROB is viewed through the eyepiece lens 15.

Also in this viewfinder, the liquid crystal display panel 10
Among the optical paths between each display section 11R, 11c, 11a and the image light combining element 6, the red image light A having a long path length is
A transparent body 1 is provided in the optical path of R and the optical path of the blue image light AB to regulate the spread of the luminous flux of the red image light and the blue image light AB.
2.12, the image lights AR, A of each color of red, green, and blue that enter the image light combining element 6 from each display section 11R, 11c, IIs of the liquid crystal display panel 10.
,.

It is possible to make the spread of the luminous flux of AB almost the same,
Therefore, each display section 11R, IIG.

The image light AR2Ao, A of each color from 11a can be made to enter the image light combining element 6 in a state in which the optical path lengths on the top are approximately equal, that is, in a state in which the brightness is approximately equal. The full-color image light A1(, B can be made into an image with good color balance.

In this embodiment, the light sources are three-color lights 11jfl 8R, 18a, 18a (red, green, blue).
However, each display section 11R111 of the liquid crystal display panel 10
In the case where red, green, and blue color filters are provided in each of the display sections 11R and 11B, the light source may be a white light source.

It is also possible to use one light source that faces all of 11B.

This also applies to the first embodiment described above.

Furthermore, in the first and second embodiments described above, each display section 11
Among the optical paths between R, 11c, and 11B and the image light combining element 6, the spread of the luminous flux of the image light AR, A is limited only to the optical path of the red image light AR and the optical path of the blue image light AB, which have long path lengths. A regulating transparent body 12.12 is interposed, but this transparent body may be provided in the optical path of image light of all colors red, green, and blue, and in that case, it may be provided in a long optical path. Depending on the difference in each optical path length, one or both of the light transmittance and the length along the light transmission direction between the transparent body and the transparent body provided in the short optical path, the apparent upper optical path length is determined. They should be selected so that they are approximately equal.

Furthermore, in the embodiment described above, the display sections 11R, 11c, and 11a that display images of red, green, and blue are formed on one liquid crystal display panel 10;
1c, 11B may be separate liquid crystal display panels, and each display section 11R, 11a,
11a is not limited to a liquid crystal display panel, but may be a cathode ray tube or the like. Further, the image light combining element 6 is not limited to a dichroic prism in which four (I1) triangular prisms are bonded together, but may also be an X-shaped dichroic prism in which dichroic mirrors are combined in an X shape.

Further, in the above embodiment, three display sections 11R111a
, I Is three-color image light Aa of red, green, and blue
,A, ,A, as one full-color image light A IIGII
Although the description has been made regarding a display device that synthesizes
B is divided into two display parts, each displaying one half of the image and the other half, and each of these two display parts makes a total of six display parts.
The green and blue image lights are combined into one full-color image light by an image light combining element, and the red 1 is placed at the position of the green image display section 11a and the red image display section 11R or the blue image display section 11B in the above embodiment. !11 A display section that displays an image of one or two colors of blue and a display section that displays an image of one or two other colors are arranged, and the image light of each color from these two display sections is arranged. It goes without saying that the present invention can be widely applied to various display devices, such as those that combine images into one full-color image light.

〔Effect of the invention〕

In the display device of the present invention, among the image light of each color that enters the image light combining element from each display section, the spread of the luminous flux of the image light that enters the image light combining element through at least a long optical path is controlled by the transparent body. By regulating the spread of the luminous flux of the image light of each color that enters the image light combining element from each display section, it is possible to make the spread of the luminous flux of the image light of each color from each display section almost the same. Since it is possible to input the light into the image light combining element in a state in which the apparent optical path lengths are approximately equal, that is, in a state in which the brightness is approximately equal, it is possible to make a full color image synthesized by the image light combining element into an image with good color balance. can.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a plan view of a liquid crystal projector, FIG. The figure is a plan view of a liquid crystal display panel on which red, green, and blue image display sections are formed. FIG. 4 is a cross-sectional plan view of a viewfinder showing a second embodiment of the present invention. FIGS. 5 and 6 are plan views of conventional display devices, respectively. 2... Light source, 3R, 3a, 3a... Dichroic mirror 4... Projection lens, 6... Image light combining element, 7... Amplifying/reversing mirror 10... Liquid crystal display panel,
1131...Red image display section, 11G-...Green image display section, 11B...Blue image display section, AR...Red image light, AC...Green image light, A...Blue image Light, 12... Transparent body, A ROB... Full color image light, 15... Eyepiece, 18R, 18G, 18a.
··light source.

Claims (1)

[Claims] A plurality of color images to create a full-color image are displayed on a plurality of display sections arranged on the same plane, and image light of each color from each display section is combined by an image light combining element to create the full-color image. In a display device that
A display device characterized in that a transparent body is interposed in at least a long optical path of each optical path between each of the display sections and the image light combining element to regulate the spread of the luminous flux of the image light.