JPH11194298A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend an optical path without using a relay lens optical system. SOLUTION: A dichroic mirror 6 transmits a red color light beam among incident light beams and reflects other color light beams. A dichroic mirror 7 transmits a blue light beam among reflected light beams and reflects a green color light beam. The red color light beam is passed through a total reflection mirror 8 and a condenser lens 10, made incident on a liquid crystal panel 13, the green color light beam is passed through a condenser lens 11 and made incident on a liquid crystal panel 14. The blue color light beam is passed through an optical waveguide 9 and a condenser lens 12 and made incident on a liquid crystal panel 15. A dichroic prism 16 synthesizes the respective color beams transmitted through the liquid crystal panels 13-15. Since the optical waveguide 9 is used, the optical path of the blue color light beam is extended and reversed without inverting the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a projection display device for enlarging and projecting an input image.

[0002]

2. Description of the Related Art A projection display device for enlarging and projecting a computer image, a video image or the like on a screen has been known. FIG. 4 is a block diagram of a conventional projection display device. The light source light emitted from the lamp 1 passes through the incident-side fly-eye lens 2, the output-side fly-eye lens 3, the polarizing beam splitter 4, and the condenser lens 5 and enters the first dichroic mirror 6. The dichroic mirror 6 transmits red light out of the light emitted from the condenser lens 5 and reflects other color lights. The second dichroic mirror 7 transmits blue light and reflects green light in the reflected light of the dichroic mirror 6. The red light transmitted through the dichroic mirror 6 passes through the total reflection mirror 8 and the condenser lens 10 and enters the liquid crystal panel 13.
The green light reflected by the dichroic mirror 7 is
The light passes through the condenser lens 11 and enters the liquid crystal panel 14. The blue light transmitted through the dichroic mirror 7 passes through the condenser lens 9a, the total reflection mirror 9b, the condenser lens 9c, the total reflection mirror 9d, and the condenser lens 12, and enters the liquid crystal panel 15. The dichroic prism 16 combines the respective color lights transmitted through the liquid crystal panels 13 to 15. And dichroic prism 1
The light synthesized by 6 is projected by a projection lens 17 onto a screen (not shown).

In such a projection display device, the liquid crystal panels 13 to 1 are arranged on three surfaces of the dichroic prism 16.
Since the red light, the green light, and the blue light that have passed through the light source 5 respectively enter, there is a problem that the optical path length of at least one color light (blue light in FIG. 4) is longer than the optical path lengths of the other color lights.
To compensate for this difference in optical path length, a relay lens optical system including a condenser lens 9a, a total reflection mirror 9b, a condenser lens 9c, and a total reflection mirror 9d is used. However, since this relay lens optical system operates in the same manner as a telescope with a magnification of 1 ×, the phase of the image is inverted only by the color light provided with the relay lens optical system. For this reason, if the illumination system has illuminance unevenness other than rotational symmetry, the distribution of the illuminance unevenness is inverted only by the color light that has passed through the relay lens optical system. As a result, the illuminance distribution changes between the color light that has passed through the relay lens optical system and the other color light that has not passed through the relay lens optical system, and appears as color unevenness on the screen. In addition, the entrance side fly-eye lens 2 and the exit side fly-eye lens 3
This is for improving the illuminance unevenness of the light source light emitted from the illuminator, but the illuminance unevenness that cannot be improved by the fly-eye lenses 2 and 3 appears as color unevenness on the screen. The above is
Although the projection type display device using a dichroic prism for the color synthesizing optical system has been described, even when a color synthesizing optical system such as a dichroic mirror is used, depending on the arrangement of the liquid crystal panel, a relay lens optical system is required, A similar phenomenon occurs.

[0004]

As described above, the conventional projection type display device has a problem that the image on the screen enlarged and projected has uneven color. It is very difficult to eliminate uneven illuminance only by assembly tolerance. For this reason, there has been a problem that color unevenness adjustment has to be performed manually by a skilled worker, and a large amount of work time is required in the manufacturing process. SUMMARY An advantage of some aspects of the invention is to provide a projection display device that can extend an optical path without using a relay lens optical system.

[0005]

According to the present invention, a light source, a color separation optical system for separating light emitted from the light source into a plurality of color lights, and the color separation optical system are provided. A plurality of light valves for modulating incident light, each disposed in the optical path of each of the separated color lights, and a plurality of incident surfaces corresponding to each of the color lights, and transmission of each light valve incident on the incident surface. A color combining optical system for combining light, a projection optical system for projecting light combined by the color combining optical system,
It has a flexible optical waveguide disposed in the optical path between the color separation optical system and each light valve, the optical path requiring reversal of the direction. Since the color synthesizing optical system has a plurality of incident surfaces corresponding to the respective color lights, it is necessary to reverse the traveling direction of at least one of the color lights in order to make each color light incident on these incident surfaces. By providing a flexible optical waveguide in the optical path of the color light, the optical path can be extended and inverted. Also, as described in claim 2,
The optical waveguide is an optical fiber.

[0006]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a projection display device showing an embodiment of the present invention. This projection display device includes a lamp 1 serving as a light source, an incident fly-eye lens 2 and an exit fly-eye lens 3 for improving illuminance unevenness of light emitted from the lamp 1, and light emitted from the fly-eye lens 3. A polarizing beam splitter 4 for aligning the polarization plane in a certain direction, a condenser lens 5 for condensing light emitted from the polarizing beam splitter 4, and a first light for transmitting red light among reflected light from the condenser lens 5 and reflecting other colored light. The dichroic mirror 6, the second dichroic mirror 7 that transmits blue light out of the reflected light of the dichroic mirror 6, the total reflection mirror 8 that reflects red light from the dichroic mirror 6, and the dichroic mirror 7 that reflects red light from the dichroic mirror 6. Optical waveguide 9 for transmitting blue light, condenser lens 1 for collecting red light from total reflection mirror 8
0, a condenser lens 11 for condensing green light from the dichroic mirror 7, a condenser lens 12 for condensing blue light from the dichroic mirror 7, and a transmission type light valve for modulating red light, green light and blue light. Liquid crystal panels 13, 14, 15; liquid crystal panels 13, 14, 15
Dichroic prism 16, which synthesizes light transmitted through
A projection lens 17 projects the light emitted from the dichroic prism 16 onto a screen or the like (not shown).

In this embodiment, the dichroic mirrors 6 and 7 constitute a color separation optical system, the dichroic prism 16 constitutes a color combining optical system, and the projection lens 17 constitutes a projection optical system. Next, the operation of such a projection display device will be described. The light source light emitted in the horizontal direction from the lamp 1 enters the incident-side fly-eye lens 2.

The incident side fly-eye lens 2 is shown in FIG.
As shown in FIG. 1, the lens is composed of a plurality of plano-convex lenses a to r. Similarly, the outgoing fly-eye lens 3 is arranged as shown in FIG.
As shown in (b), the lens is composed of a plurality of plano-convex lenses a ′ to r ′ corresponding to the lenses a to r, respectively (corresponding lenses are aa ′, bb ′, and cc). ', ...
・ ・).

As shown in FIG. 3, the light radiated from the lamp 1 passes through the incident-side fly-eye lens 2 and has a converging property. Thereby, a plurality of light source images are formed on the emission side fly-eye lens 3. Then, the light beam split by the individual lenses a to r of the incident-side fly-eye lens 2 is irradiated by the emission-side fly-eye lens 3 onto the illuminated surface (in the present embodiment,
The liquid crystal panels 13 to 15) are irradiated with an image. Thus,
A good irradiation state without unevenness in illuminance and chromaticity on the irradiated surface can be obtained.

The light exiting the exit fly-eye lens 3 passes through a polarizing beam splitter (PBS) 4 and a condenser lens 5 and enters a first dichroic mirror 6. The polarization beam splitter 4 aligns the polarization plane of the emitted light in a certain direction. Subsequently, the first dichroic mirror 6 transmits only the red light of the light emitted from the condenser lens 5 and reflects the other color lights in the vertical direction.

The light reflected by the first dichroic mirror 6 enters a second dichroic mirror 7. The second dichroic mirror 7 transmits only the blue light of the reflected light of the dichroic mirror 6 and reflects the other color light, that is, the green light in the horizontal direction.

The red light transmitted through the dichroic mirror 6 enters the total reflection mirror 8. The total reflection mirror 8 reflects the red light in the vertical direction and guides the red light to the condenser lens 10. The red light that has passed through the condenser lens 10 enters the liquid crystal panel 13. The green light reflected by the dichroic mirror 7 passes through the condenser lens 11 and enters the liquid crystal panel 14.

Then, the blue light transmitted through the dichroic mirror 7 enters the optical waveguide 9. The optical waveguide 9 is, for example, a bundle of a plurality of optical fibers, and has a feature of being highly flexible. Therefore, the optical waveguide 9 can be curved as shown in FIG. 1, whereby the traveling direction of the blue light can be reversed. The light traveling through the optical waveguide 9 and emitted from the optical waveguide 9 passes through the condenser lens 12 and enters the liquid crystal panel 15.

On the other hand, R,
Driving circuit (not shown) that receives G and B input image signals
Converts these into R, G, B liquid crystal drive signals and outputs them to the liquid crystal panels 13 to 15, respectively. This allows
An image relating to the R component of the input image is displayed on the liquid crystal panel 13 to which the R liquid crystal drive signal is input, and an image relating to the G component of the input image is displayed to the liquid crystal panel 14 which receives the G liquid crystal drive signal. Then, an image relating to the B component of the input image is displayed on the liquid crystal panel 15 to which the B liquid crystal drive signal is input.

Thus, the red light, green light, and blue light incident on the liquid crystal panels 13 to 15 are modulated according to the input image signal. Next, the dichroic prism 16 combines the red light, green light, and blue light transmitted through the liquid crystal panels 13 to 15. The dichroic prism 16 is obtained by bonding four right-angle prisms and forming a dichroic layer on the bonded surface, and three of the outer walls constitute an incident surface.

The liquid crystal panels 13 to 15 are arranged so as to face the respective incident surfaces of the dichroic prism 16 corresponding to red light, green light and blue light, respectively. Accordingly, the dichroic prism 16 transmits the green light emitted from the liquid crystal panel 14 and reflects the red light and the blue light emitted from the liquid crystal panels 13 and 15 to combine the respective color lights.
Finally, the light synthesized by the dichroic prism 16 is projected by a projection lens 17 onto a screen (not shown).

As described above, according to the present invention, by using the optical waveguide 9 instead of using the relay lens optical system, the optical path of the blue light can be extended and inverted without inverting the image. It becomes possible.

The use of the optical waveguide 9 reduces the amount of blue light, which can be compensated for by the following method. (1) A second dichroic mirror 7 having better transmission characteristics than the first dichroic mirror 6 is used. (2) The transmittance of the liquid crystal panel 15 for blue light is corrected to be higher, or the transmittance of the liquid crystal panel 13 for red light and the liquid crystal panel 14 for green light is corrected to be lower.
The control signal from the driving circuit is corrected.

In this embodiment, the optical waveguide 9 is provided in the optical path of blue light. However, it may be provided in the optical path of another color light depending on the configuration of the optical system. Needless to say, it may be provided at In the present embodiment, the dichroic prism 16 is used as the color combining optical system. However, it is needless to say that the present invention can be applied to a case where a color combining optical system (a dichroic mirror or the like) other than the dichroic prism is used.

[0020]

According to the present invention, the relay lens optical system is used by providing a flexible optical waveguide in the optical path between the color separation optical system and each light valve, the optical path of which direction needs to be reversed. Without this, the optical path can be extended and inverted. As a result, it is possible to reduce color unevenness that occurs in an image on a screen, so that it is possible to simplify a delicate adjustment operation in a manufacturing process, and to shorten an adjustment time, thereby reducing a manufacturing cost. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram of a projection display device showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a structure of a fly-eye lens.

FIG. 3 is a diagram for explaining the principle of a fly-eye lens.

FIG. 4 is a block diagram of a conventional projection display device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 lamp, 2 entrance fly-eye lens, 3 exit fly-eye lens, 4 polarization beam splitter, 5 condenser lens, 6 first dichroic mirror, 7
... second dichroic mirror, 8 ... total reflection mirror, 9
... Optical waveguide, 10-12 ... Condenser lens, 13-1
5 liquid crystal panel, 16 dichroic prism, 17
... projection lens.

Claims (2)

[Claims] 1. A light source, a color separation optical system for separating light emitted from the light source into a plurality of color lights, and an incident light disposed in an optical path of each color light separated by the color separation optical system. A plurality of light valves for modulating the light, a plurality of incident surfaces corresponding to the respective color lights, and a color synthesizing optical system for synthesizing transmitted light of each light valve incident on the incident surface; A projection optical system for projecting the reflected light, and a flexible optical waveguide disposed in the optical path between the color separation optical system and each light valve, the optical path of which direction needs to be reversed. Type display device. 2. The projection display device according to claim 1, wherein the optical waveguide is an optical fiber.