JPH10246868A - Projection type video display - Google Patents

Abstract

(57) [Problem] To improve light efficiency by reducing luminance unevenness due to gravitational influence of a light source with a simple configuration and without changing the optical path length, and to enable cost reduction and miniaturization. SOLUTION: A cylindrical fly-eye lens element 23, a diaphragm 24 and a relay lens 25 are arranged between a parabolic reflector 22a and a liquid crystal light valve 26. The light in the vertical direction from the light source is split into a plurality of light beams by a first fly-eye lens element 23a, and the split light is irradiated by the second fly-eye lens element 23b so as to overlap the entire liquid crystal light valve 26. Also,
The angle of the light in the horizontal direction is limited by the stop 24 within the allowable horizontal divergence angle θ. Thereby, the light efficiency can be improved without changing the optical path length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal projector using a light source lamp and a liquid crystal light valve, or a projection type image display device such as a projection type liquid crystal projection television.

[0002]

2. Description of the Related Art In recent years, a projection type liquid crystal projector using a liquid crystal panel (hereinafter, referred to as a projection type image display device) has attracted attention with a demand for a large screen, small size and light weight display device. By using a liquid crystal panel, a projection-type image display device can be made smaller and lighter than a projection-type image display device using a conventional CRT, and can easily realize a large-screen display. In addition, there is an advantage that troublesome convergence adjustment is not required and there is no influence of geomagnetism. For these reasons, the projection-type image display devices are currently spreading rapidly.

Generally, in a projection type video display device,
The screen gets darker as it gets bigger. In other words, the larger the screen, the more difficult it is to realize a bright screen. Also, if the room in which the projected image is viewed is not dark but is to be viewed in a slightly bright room, the projected image may be difficult to see. For this reason, in order to expand the range of use of the projection type image display device, it is desired to improve the brightness so that a bright image can be projected even on a large screen and can be recognized even in a slightly bright room.

FIG. 5 is a principle view showing a configuration of an illumination optical system in a general projection type video display device.

As shown in FIG. 5, in a general projection type image display apparatus, light emitted from a light source lamp 1 is controlled and reflected by a parabolic mirror 2 into substantially parallel light, for example.
Then, the image formed on the liquid crystal light valve 5 is magnified and formed on the screen 8 by the light projecting lens 7 to perform the function as a projection type image display projector device.

[0006] The illumination system of such a projection type video display device has a simple structure and is advantageous in cost and installation space, but tends to cause uneven illumination. For this reason, frost processing is performed on the lamp tube to perform diffusion irradiation at the expense of efficiency, thereby achieving an acceptable level of illuminance unevenness. Therefore, in such a method, the light use efficiency is low, and this problem is remarkable especially in recent years in which the size of the panel is reduced.

As means for solving this problem, improvement means using a fly-eye lens is currently most commonly used. FIG. 6 shows an example of a projection type video display device employing such an improvement means.

FIG. 6 is an optical system configuration diagram showing an example of a projection type video display apparatus to which an improvement means using a fly-eye lens is applied.

As shown in FIG. 6, in this method, light emitted from a parabolic mirror 2 is subdivided by a fly-eye lens 3 by a lens array having the same aspect ratio as an illumination image.
One to one lens array subdivided into each imaging position
Each fly-eye element image of the fly-eye lens 3 is converted into a liquid-crystal light valve 5 by a fly-eye lens 4 having a corresponding configuration.
Is imaged on the entire surface or in an arbitrary range. As a result, it is possible to average the luminance imbalance due to the above-described factors and obtain high-quality light source illumination.

However, when viewed from the entrance side of a liquid crystal cell (LCD), this method is equivalent to the existence of a large number of virtual light sources dispersed in an arbitrary range, so that a large divergent incident angle of light is efficiently transmitted to the screen. It is necessary to provide an optical system that performs

Further, with the development of polysilicon liquid crystal, liquid crystal light valves have been further miniaturized. However, in the single-panel system using a conventional color filter, any one of RGB light for irradiating an arbitrary cell is used. Since light passes through only a single color band, the efficiency of light utilization becomes a problem. At the same time, most of the lost light becomes heat, which causes problems such as the light resistance of the color filter. It is.

In order to solve the above-mentioned problems, a color display method using microlens focusing and angle control as shown in FIG. 7 has been proposed.

In this proposal, as shown in FIG. 7, a microlens 9 (for example, a lens member is injected into a plurality of holes provided in a glass plate and molded through a counter substrate 20 for each pixel of a liquid crystal cell 11). , A liquid crystal panel is formed, and by changing the light condensing position by the microlens 9 (the incident angle of RGB with respect to the microlens 9), color display can be performed without using a color filter. I do.

However, in this method, the divergence angle of the illumination light beam is restricted in principle. That is, if the angle exceeds the limit angle “θ”, any one of the RGB light beams is not irradiated to the dot to be irradiated and is not irradiated to the adjacent dot. Irradiate the dots (cells), and as a result, the color purity cannot be ensured.

For this reason, in this method, the stop 13 as shown in FIG. 8 is indispensable, and measures against color purity loss are taken by limiting the divergence angle of illumination by the stop 13. The aperture diameter “φ” is determined by the illumination limit divergence angle (allowable incident angle θ) determined by the panel and the collimator lens 14 to the liquid crystal panel 15.
If the optical path length is sufficiently ensured, the allowable incident angle θ can be increased. Conversely, if only the conventional optical path length is ensured, the aperture diameter “φ” decreases. However, if the aperture diameter “φ” is reduced, not only the fly-eye illumination system described above cannot be applied, but also a large amount of light is blocked by the aperture, and even if a high-power lamp is used, light utilization cannot be ensured. A problem occurred efficiently.

Further, if the resolution is advanced by the color separation method by the angle control, the limit error of the microlens itself cannot be ignored, and in the actual illumination system, the allowable incident divergence angle is narrower than the range shown in FIG. At present, sufficient color purity cannot be ensured unless it is limited to this.

Further, in the present method, if the pixel pitch is made smaller in order to increase the number of pixels, the allowable angle of incidence is further reduced, so that more light beams are lost, which is not suitable for high definition display. there were. To solve this problem, the allowable incident angle can be recovered by further reducing the thickness of the counter substrate 10. However, such improvement results in an increase in the divergence angle after passing through the light valve, as shown in FIG. 9, for example. Therefore, it is necessary to reduce the F-number of the projection lens,
As a result, disadvantages such as an increase in cost and an increase in shape are generated.
Further, the focal length of the microlens becomes shorter as the projection lens becomes larger and the counter substrate 10 becomes thinner.
The radius becomes smaller, that is, the influence on the manufacturing accuracy of the microlens becomes great, and the situation is contradictory in a situation where the manufacturing of the microlens is required to be simplified.

Taking the above conditions into consideration, a fly-eye lens illumination system which expands the illumination divergence angle in principle cannot apply a color separation illumination system by angle control or cannot avoid a long optical path length. There was a problem that a system could not be constructed.

[0019]

As described above, the conventional projection type image display apparatus capable of color display by angle control can be reduced in size and cost because it is a single-panel type, and the dichroic mirror can be used. While light utilization efficiency comparable to that of the three-plate system can be obtained, there is an efficiency loss due to divergence angle limitation, and at the same time it is unsuitable for increasing the definition of multiple pixels. However, there is an inconvenience that a long optical path length is required to store the light in the optical path. In order to stay within the normal optical path length because the divergence angle needs to be sufficiently narrow, illuminance unevenness caused by the light source is allowed, or an illumination average that efficiently averages by securing a long optical path length equivalent to a three-plate system Although it is necessary to use a light source, it has not been actually developed, and therefore, it is not possible to reduce the luminance unevenness due to the gravitational effect of the light source with a normal optical path length, and as a result, the light efficiency is degraded. In addition, there is a problem that cost reduction and size reduction cannot be achieved.

Accordingly, the present invention has been made in view of the above problems, and has a simple structure that reduces the unevenness of brightness due to the gravitational effect of the light source without changing the optical path length, thereby improving the light efficiency and reducing the cost. It is an object of the present invention to provide a projection-type image display device that can be reduced in size and size.

[0021]

According to a first aspect of the present invention, there is provided a projection type image display device, wherein a parabolic reflector for reflecting light emitted from a light source having a predetermined light emission range substantially parallel to an optical axis; A liquid crystal light valve that modulates light reflected by the parabolic reflector; and a first light that is interposed between the parabolic reflector and the liquid crystal light valve and that reflects only the vertical direction reflected by the parabolic reflector. The light is divided into a plurality by a fly-eye lens element, and the divided light is
The first fly-eye lens element is configured to irradiate the first fly-eye lens element in an extended illumination range according to the aspect ratio of the liquid crystal light valve. For enlarging and irradiating with a cylindrical fly-eye lens element having an arbitrary curved surface and the first fly-eye lens element. A relay lens for changing and irradiating the light, a second fly-eye lens element, and a relay lens disposed at a condensing position of the relay lens to limit an angle only in a horizontal direction of light from the second fly-eye lens element Squeezing means.

According to the first aspect of the present invention, the parabolic reflector reflects light emitted from a light source having a predetermined light emission range substantially parallel to the optical axis. The liquid crystal light valve modulates the light reflected by the parabolic reflector. At this time, the cylindrical fly-eye lens element is interposed between the parabolic reflector and the liquid crystal light valve, and emits only vertical light reflected by the parabolic reflector on the first fly-eye lens element. And irradiates the divided light with the second fly-eye lens element so as to be superimposed on the entire liquid crystal light valve. The first fly-eye lens element includes the liquid crystal light. An arbitrary curved surface for enlarging and irradiating the illumination range according to the aspect ratio of the bulb is provided. The relay lens is configured to perform enlarged irradiation with the first fly-eye lens element, and irradiates the light from the second fly-eye lens element while changing the irradiation range only in the horizontal direction. The aperture means is disposed at a condensing position of the second fly-eye lens element and the relay lens, and limits an angle only in a horizontal direction of light from the second fly-eye lens element. Therefore, the angle limited by the single-plate light valve system by angle control can be limited to one horizontal or vertical direction, so that the direction in which the limited angle exists does not increase the divergence angle in the form of a relay lens. Take
In this vertical direction, it is possible to take a cylindrical fly-eye configuration that takes a fly-eye configuration. As a result, luminance unevenness due to the gravitational effect of the light source can be reduced with the minimum optical path length extension.

According to a third aspect of the present invention, there is provided a projection display apparatus according to the present invention, wherein the light emitted from a light source having a predetermined light emission range is condensed at an arbitrary position on an optical axis, and the light is reflected by the elliptical reflector. A liquid crystal light valve that modulates the reflected light, and a light only in the vertical direction, which is interposed between the elliptical reflector and the liquid crystal light valve and is reflected by the elliptical reflector, is divided into a plurality by a first fly-eye lens element. And a cylindrical fly-eye lens element configured to irradiate the split light with the second fly-eye lens element so as to be superimposed on the entire liquid crystal light valve, and a light source for the light from the cylindrical fly-eye lens element. Diaphragm means capable of limiting the angle only in the horizontal direction, and converting the liquid principal ray, which has passed through the diaphragm means, into parallel light parallel to the optical axis at an arbitrary position. It is obtained by including a cylinder lens for irradiating the light valve.

According to the third aspect of the present invention, the elliptical reflector collects light emitted from a light source having a predetermined light emission range at an arbitrary position on the optical axis. The liquid crystal light valve modulates the light reflected by the elliptical reflector. At this time, the cylindrical fly-eye lens element is interposed between the elliptical reflector and the liquid crystal light valve,
Splitting the light only in the vertical direction reflected by the elliptical reflector into a plurality of pieces by a first fly-eye lens element,
The split light is superimposed on the entire liquid crystal light valve and irradiated by the second fly-eye lens element. The diaphragm means restricts the angle only in the horizontal direction of the light from the cylindrical fly-eye lens element. The cylinder lens converts the principal ray of the light beam that has passed through the aperture means into a parallel light beam parallel to the optical axis at an arbitrary position, and irradiates the liquid crystal light valve. Accordingly, in addition to obtaining the same light as in the above-described invention, the number of components can be reduced, which can contribute to cost reduction and miniaturization.

According to a sixth aspect of the present invention, there is provided a projection type image display device, wherein the light emitted from a light source having a predetermined light emission range is condensed at an arbitrary position on the optical axis, and the light is emitted from the elliptical reflector. A condenser lens that converts light into parallel light that is substantially parallel to the optical axis, a liquid crystal light valve that modulates light from the elliptical reflector, and a liquid crystal light valve that is interposed between the condenser lens and the liquid crystal light valve. The light only in the vertical direction from the condenser lens is split into a plurality of light beams by a first fly-eye lens element, and the split light is irradiated by being superimposed on the entire liquid crystal light valve by a second fly-eye lens element. A cylindrical fly-eye lens element, each of which has a phase for condensing light in the horizontal direction on these elements, the first fly-eye lens element, and the second fly-eye lens element. Disposed converging position of the lens element, in which anda throttle means capable only in the horizontal direction the angle limit of the light from the first fly-eye lens element.

In the sixth aspect of the present invention, the elliptical reflector collects light emitted from a light source having a predetermined light emission range at an arbitrary position on the optical axis. The condenser lens converts light emitted from the elliptical reflector into parallel light that is substantially parallel to the optical axis. A liquid crystal light valve modulates light from the elliptical reflector. At this time, the cylindrical fly-eye lens element is interposed between the condenser lens and the liquid crystal light valve, and divides the light only in the vertical direction from the condenser lens into a plurality of parts by the first fly-eye lens element. And
The divided light is configured to be irradiated by being superimposed on the entire liquid crystal light valve by the second fly-eye lens element, and each of the elements has a phase of condensing light in the horizontal direction on these elements. . In addition, the aperture means is provided in the first
And the second fly-eye lens element are disposed at the condensing positions of the second fly-eye lens element and limit the angle of only the horizontal direction of the light from the first fly-eye lens element. Thereby, while obtaining the same effect as the above invention, when both polarizing elements are used for the condenser lens, it is possible to further reduce the size, increase the high school rate, and equalize the left and right light amounts,
A high-quality illumination optical system can be constructed.

[0027]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of an optical system showing a first embodiment of a projection type video display apparatus according to the present invention.
FIG. 1B is a top view of the apparatus, FIG. 1B is a side view, and FIG. 1C is an explanatory view for explaining functions in the apparatus. It should be noted that the liquid crystal light valve 26 used in the apparatus of FIG. 1 is of a microlens type, and for simplification of description, a predetermined number of light rays in the optical system are shown, and aberrations of the lens and the like are shown. It is assumed that there is no.

In the projection type video display of the present invention,
As shown in the figure, because of the color separation configuration using the horizontal angle deviation, there is no vertical critical angle that causes a problem, and the effective efficiency divergence angle only depends on the aperture shape of each pixel. It is.

For example, assuming that the arrangement pattern of the RGB openings in the liquid crystal cell is a stripe arrangement, the vertical arrangement width is about three times as large as the normal horizontal opening width in the stripe arrangement. Is expected to be about three times the allowable horizontal incident angle without losing the angle.

Therefore, in the present embodiment, a fly-eye lens configuration in which the irradiation angle is enlarged only in the vertical direction is employed, and a relay lens configuration in which the illumination divergence restriction angle is allowed in the horizontal direction is employed. In a severe horizontal direction, consideration is made to minimize loss of the illuminance distribution and the divergence angle state immediately after emission from the reflector. In other words, in the horizontal direction caused by uneven illuminance, the illumination divergence limit angle incident on the liquid crystal light valve is reduced, and in the vertical direction,
In order to improve the light efficiency as much as possible, the vertical incidence angle of the light beam is enlarged.

Next, the configuration and functions of the apparatus of the present invention will be described separately in the horizontal and vertical directions for simplicity.

First, the horizontal direction will be described.
As shown in (a), the light emitted from the light source 21 is controlled and reflected by the parabolic reflector 22 substantially in parallel with the optical axis. The irradiation light is applied to a cylindrical fly-eye lens element (hereinafter, abbreviated as fly-eye lens element) 23 formed in a cylindrical shape as an optical unit.

The fly-eye lens element 23 is disposed so as to be interposed between the parabolic reflector 22 and the stop 24, as shown in FIG.
, And a second fly-eye lens 23b. Since the first fly-eye element 23a is formed by a lens and a fly-eye lens, the first fly-eye element 23a operates so as to reduce the divergence angle of illumination with respect to the incident surface of the liquid crystal light valve 26 with respect to the horizontal irradiation light beam. Also, in the vertical direction, the operation is performed so as to increase the divergence angle of the illumination.

On the other hand, the second fly-eye lens element 23b
Is formed so as to be in a relay lens form, so that the illuminating light beam in the horizontal direction is operated to pass as it is, and the first fly-eye lens element 23a is operated only in the vertical direction. In the same manner as described above, the illumination divergence angle is increased.

Therefore, the fly-eye lens element 23a configured as described above irradiates the irradiated light beam to the second fly-eye lens element 23b, and the irradiated light beam passes through the second fly-eye lens element 23b. Diaphragm 24 through
Is irradiated. That is, the irradiation light beam is focused on the stop 24 by the first fly-eye lens element 23a.

The aperture 24 limits the divergence of illumination within the horizontal allowable divergence angle “θ” determined by the liquid crystal light valve 7. After that, the irradiation light that has passed through the stop 24 becomes substantially parallel to the optical axis at an arbitrary enlarged position and irradiates the liquid crystal light valve 26 by the cylindrical relay lens 25 that contributes only in the horizontal direction.

Next, the vertical direction will be described.
As shown in (b), the light emitted from the light source 21 is controlled and reflected by the parabolic reflector 22 substantially in parallel with the optical axis.
This irradiation light is applied to the fly-eye lens element 23 in the same manner as in the horizontal direction.

However, the irradiation light at this time is divided into N by the first fly-eye lens element 23a.
Each of the divided irradiation lights has an irradiation angle expanded by the opposing second fly-eye lens element 23b and irradiates the entire liquid crystal light valve 26. That is, first,
The second fly-eye lens elements 23a and 24b function as the fly-eye lens element 23, so that the N-divided irradiation light is irradiated onto the liquid crystal light valve 26, respectively, so that the light efficiency is improved. .

In this case, since the cylindrical relay lens 25 has a relay lens form in which the irradiation light passes at the same incident angle in the vertical direction, the irradiation light is applied only in the horizontal direction. It is possible to irradiate the liquid crystal light valve 26 by refracting it within the illumination divergence limit angle.

Therefore, the horizontal direction can be limited to the divergence angle of illumination which does not cause a problem by installing the diaphragm 5 at the condensing position by the fly-eye lens 23a, and the vertical direction mainly caused by gravity can be restricted. Light emission unevenness is averaged by the two fly-eye lens elements 23a and 23b, so that it is possible to efficiently irradiate the light valve with high-quality illumination light.

In the present embodiment, the liquid crystal light valve 26
Assuming that the arrangement pattern of the RGB openings of the liquid crystal cell in the above is a stripe arrangement, the vertical opening width is about three times as large as the horizontal opening width as described above. The incident angle range is approximately three times the allowable horizontal incident angle. For this reason, when the optical system in the projection type image display device is actually constructed, if the effective angle in the vertical direction of the liquid crystal light valve 26 is about three times the divergence angle of the horizontal illumination, the optical system is surely constructed. It is possible to build.

Therefore, the apparatus of this embodiment is the same as that of FIG.
As shown in the side view of FIG. 1C, the effective angle in the vertical direction of the liquid crystal light valve 26 is about three times the horizontal divergence angle (see FIG. 1A). It is possible to construct an optimal optical system in a video display device.

If the vertical chief ray needs to be parallel to the optical axis due to the viewing angle characteristics of the liquid crystal light valve 26 or the like, a curvature is provided on the vertical surface of the cylinder-shaped relay lens 25 to allow it. The chief ray divergence angle may be set within the range. Thereby, the same effect can be obtained.

In the present invention, by using an elliptical reflector instead of the parabolic reflector 22 used in the above embodiment, it is possible to further reduce the size and cost. FIG. 2 shows such an embodiment.
Shown in

FIG. 2 shows a second embodiment of the projection type image display apparatus according to the present invention. FIG. 2 (a) is a top view of the apparatus for explaining the horizontal direction of irradiation light, and FIG. 2 (b). Is a side view of the device for explaining the vertical direction of the irradiation light, and FIG. 2C is an explanatory diagram for explaining the function of the device. In FIG. 2, the same components as those in FIG.

In this embodiment, the parabolic reflector 22 in the above embodiment is replaced with an elliptical reflector 22a, and the lens of the first fly-eye lens element 23a is deleted in accordance with this change. The point that the formed fly-eye lens element 23c is provided is different from the embodiment described above.

As shown in FIG. 2A, in this embodiment, the respective functions are the same as those in the above-described embodiment, but since the light collecting characteristics of the elliptical reflector 22a by the elliptical mirror are used, It is possible to abolish the light collecting function of the first fly-eye lens element 23a in the above embodiment. That is, the convex lens formed on the first fly-eye lens element 23a can be eliminated.

Therefore, in the case of the horizontal direction, the light source 2
The light emitted from 1a is controlled and reflected by the elliptical reflector 22a so as to converge on a stop 24 provided at a predetermined position. At this time, since the first and second fly-eye lens elements 23c and 23b are formed so as to be refracted only in the vertical direction, the irradiation light is stopped at the same incident angle.
It will lead to 4. Thereby, the divergence angle of illumination of the liquid crystal light valve 26a in the horizontal direction can be kept within the same limits as in the embodiment.

On the other hand, in the vertical direction, as shown in FIG. 2B, the first and second fly-eye lens elements 23
Due to c and 23b, the reflected light from the elliptical reflector 22a operates so as to be divided into N and the divergence angle of illumination is enlarged, so that it is possible to irradiate the liquid crystal light valve 26a. Thereby, the same effect as in the above-described embodiment can be obtained.

That is, in this embodiment, FIG.
As shown in FIG. 1C, the effective angle in the vertical direction of the liquid crystal light valve 26a is about three times as large as the horizontal divergence angle (see FIG. 1A). Thus, it is possible to construct an optimal optical system in the projection type video display device.

In this embodiment, similarly to the above-described embodiment, if the vertical principal ray needs to be parallel to the optical axis due to the viewing angle characteristics of the liquid crystal light valve 26a, etc. A curvature may be provided on the vertical surface of the cylindrical relay lens 25, and the chief ray divergence angle may be set within an allowable range.

Further, the allowable divergence angle in the horizontal direction determined by the liquid crystal size, the pixel pitch and the opposing thickness, the NA of the projection lens (see FIG. 6), and the precision of the micro lens is secured to an arbitrary value or more. If the emission distribution is sufficiently small and the conditions are matched so that the illumination divergence angle emitted from the reflector 21a is equal to or less than an arbitrary angle, for example, the relay lens 25 and the first and second fly-eye lens elements 23c and 23b By using the optical system member configured by combining the respective functions, the number of parts can be reduced.

Therefore, according to the present embodiment, since the light condensing by the elliptical mirror is used, the light condensing function by the first fly-eye lens element 23a can be eliminated, and the productivity is improved. And the present invention can be applied to a lens element group smaller than a UVIR filter or the like. This makes it possible to reduce the size and cost.

By the way, when the above-mentioned conditions are satisfied, it is possible to further reduce the size compared to the first and second embodiments. FIG. 3 shows an application example of such a projection type video display device.

FIG. 3 shows a third embodiment of the projection type image display apparatus according to the present invention. FIG. 3 (a) is a top view of the apparatus for explaining the horizontal direction of irradiation light, and FIG. ) Is a side view of the device for explaining the vertical direction of the irradiation light, and FIG.
FIG. 4 is an explanatory diagram for explaining functions of the device. FIG.
2, the same reference numerals are given to the constituent elements as in FIG. 2 and the description is omitted, and only different parts are described for simplification of the description.

In the projection type image display device of this embodiment, the allowable horizontal divergence angle determined by the size of the liquid crystal, the pixel pitch and the opposing thickness, the NA of the projection lens (see FIG. 6), and the accuracy of the microlens is an arbitrary value. On the other hand, the light emission distribution of the light source lamp 21a is sufficiently reduced, and the condition that the divergence angle of illumination emitted from the reflector 21a is equal to or less than an arbitrary angle is satisfied.

More specifically, as shown in FIG. 3A, the projection type video display apparatus has an optical system element group (30, 31,...) For averaging the light emitted from the light source 1 and improving the efficiency. 3
4 to 36), and on the irradiation direction side,
First optical element 27, stop 28, and second optical element 29
Are arranged. This first optical element 27 is
It has the function of the fly-eye lens element 23a in the embodiment.

The second optical element 29 is formed by combining the respective functions of the relay lens element 25 and the second fly-eye lens element 23b which have been separated so far. This means that the number of parts is reduced as compared with the first embodiment.

In this embodiment, as a newly provided optical system element group, a PBS 30 serving as both polarizing elements is used.
And phase difference plate 31, and mirrors 34 and 3 as reflection plates
5, and a prism sheet 36 for superimposing these reflected lights is added.

The PBS 30 has a function as both polarizing elements, and transmits P-polarized light and reflects S-polarized light. Thereafter, the P-polarized irradiation light is reflected by the mirror 34 inclined at, for example, 52.5 degrees through the phase difference plate 31 and is irradiated on the prism sheet 36. At the same time, the S-polarized irradiation light is reflected by the mirror 35 inclined at, for example, 37.5 degrees via the phase difference plate 35 and is irradiated on the prism sheet 36.

The prism sheet 36 refracts each incident light substantially parallel to obtain parallel light, and irradiates the optical element 27 with square light. Thereafter, by operating as described above, effects similar to those of the above-described embodiment can be obtained.

In this embodiment, as shown in FIG. 3C, the liquid crystal light valve 26 is similar to the embodiment.
Since the effective angle of a in the vertical direction is about three times as large as the illumination divergence angle in the horizontal direction (see FIG. 1A),
Accordingly, it is possible to construct an optimal optical system in the projection type video display device.Accordingly, according to this embodiment, the same effects as those of the above-described embodiment can be obtained, and the efficiency can be improved by using both polarizing elements. The superimposition based on the left-right mirror image relationship can realize higher efficiency and higher quality by left-right averaging. In addition, it can contribute to downsizing of the liquid crystal light valve, and it is possible to realize downsizing of the entire device.

In the present invention, the elliptical reflector 2
After condensing by 2a, a lens means 37 for intentionally generating pincushion distortion is arranged, and by applying the function of the present invention to the lens and thereafter, it is also possible to reduce peripheral light quantity deterioration. An example of such an embodiment is shown in FIG.

FIG. 4 shows a fourth embodiment of the projection type image display apparatus according to the present invention. FIG. 4 (a) is a side view of the apparatus for explaining the vertical direction of irradiation light, and FIG. 4 (b). Is a luminance distribution diagram for explaining the operation, and FIG.
This is the case when shown in a two-dimensional graphic.

In the present embodiment, the elliptical reflector 22a
The lens means 37 for intentionally generating pincushion distortion of the incident light is interposed between the cylindrical fly-eye elements 39 and 40 of the present invention including the relay lens 38.

Therefore, the light emitted from the light source 21a is
The light is condensed by the elliptical reflector 22a, and is then irradiated on the lens means 37. Thereafter, the incident light is refracted by the lens means 3 so as to generate pincushion distortion,
The liquid crystal light valve 41 is irradiated via the relay lens 38 and the cylindrical fly-eye elements 39 and 40 in a state where the pincushion distortion portion is superimposed.

FIG. 4 shows an illuminance distribution diagram of an arbitrary portion at this time.
(B) and FIG. 4 (c). That is, FIG.
In (b), the liquid crystal light valve 41 is in the vicinity of the H position before the light is condensed by the elliptical reflector 22a, in the vicinity of the I position after passing through the lens means 37, and in the liquid crystal light valve 41 after passing through the cylindrical fly-eye elements 39 and 40. The illuminance distribution is shown in a plane at J points, and in FIG.
The illuminance distribution in the vicinity of the location and in the vicinity of the J location are shown by three-dimensional graphics so that they can be understood at a glance.

Therefore, as can be seen from these figures, the illumination light emitted from the lens means 37 undergoes pincushion distortion as shown in the illuminance distribution diagram near the point I in FIG. 4 (b). As shown in the illuminance distribution diagram near the J point in FIG. 4B, the strained lattice portion in the illuminance distribution diagram (near the I position) is changed by the cylindrical fly-eye elements 39 and 40 according to the present invention. Will be superimposed. Therefore, as shown in FIG. 4C, on the surface of the liquid crystal light valve 41, the light amount at the four corners increases, and the light amount can also be increased on average over the entire surface.
It is possible to prevent deterioration of the peripheral light amount.

Therefore, according to the present embodiment, pincushion distortion is generated in the irradiation light from the elliptical reflector 22a by the lens means 37, and then the strained grating portions are superimposed by the cylindrical fly-eye lens elements 39 and 40, respectively. This makes it possible to increase the amount of peripheral light in the planar state of the liquid crystal light valve, and as a result, it is possible to construct a more desirable illumination optical system in the projection type image display apparatus.

In the third and fourth embodiments according to the present invention, like the first and second embodiments, the viewing angle characteristics of the liquid crystal light valve 26a or 41 are used.
If the vertical chief ray needs to be parallel to the optical axis, a curvature is provided on the vertical surface of the ray lens in the second optical element 29 or 40, and the chief ray divergence angle is set within an allowable range. It may be adjusted as follows.

[0072]

As described above, according to the present invention,
Since the influence of gravity, which is a main cause of unbalance of the lamp light source, can be reduced with a simple configuration without changing the optical path length, the light efficiency can be improved. In addition, the use of an elliptical mirror makes it possible to reduce the size of the fly-eye lens, thereby contributing to a reduction in the optical path length and cost, and also to improve the manufacturability by reducing the power of each lens element. Become.

Further, the present invention can be applied to an illumination optical system having the same number of elements as the fly-eye illumination system by combining the respective functions, or to an element utilizing both polarizations. By applying the present invention to an illumination system having pincushion distortion, The peripheral light amount can be improved. As a result, the illuminance unevenness is averaged while securing the angle information, so that it is possible to provide a more efficient and higher-quality projection-type image display device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a lighting device for a liquid crystal projector according to the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the illumination device for a liquid crystal projector according to the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of the illumination device for a liquid crystal projector according to the present invention.

FIG. 4 is a configuration diagram showing a fourth embodiment of the illumination device for a liquid crystal projector according to the present invention.

FIG. 5 is a principle diagram of an illumination optical system of the liquid crystal light valve type projector.

FIG. 6 is a schematic configuration diagram of an illumination optical system using a conventional fly-eye lens.

FIG. 7 is a principle diagram showing a color separation method based on angles.

FIG. 8 is a schematic diagram of an angle-limited illumination optical system using a stop and a condenser lens.

FIG. 9 is a principle diagram for explaining an increase in the projection lens load due to a reduction in the thickness of the counter substrate.

[Explanation of symbols]

21, 21a ... light source, 22a ... parabolic reflector, 22
b: elliptical reflector, 23, 23a, 23b: cylindrical fly-eye lens element, 24: stop, 25: cylindrical relay lens, 26: liquid crystal light valve, Fno: brightness index of optical system, Fno = 1 / (2n sin u) u: Maximum focusing angle * NA · F = 0.5

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09F 9/00 360 G09F 9/00 360K H04N 9/31 H04N 9/31 C

Claims (6)

[Claims] A parabolic reflector that reflects light emitted from a light source having a predetermined light emission range substantially parallel to an optical axis; a liquid crystal light valve that modulates light reflected by the parabolic reflector; Interposed between the parabolic reflector and the liquid crystal light valve, the light only in the vertical direction reflected by the parabolic reflector is split into a plurality of lights by a first fly-eye lens element, and the split light is The second fly-eye lens element is configured to irradiate the liquid crystal light valve so as to be superimposed on the entire liquid crystal light valve. The first fly-eye lens element is extended to an illumination range according to an aspect ratio of the liquid crystal light valve. The first fly-eye lens element has a cylindrical fly-eye lens element having an arbitrary curved surface for irradiation, and the first fly-eye lens element is used to perform enlarged irradiation. A relay lens for changing the irradiation range of the light from the eye lens element only in the horizontal direction and irradiating the light, and a second fly eye disposed at a condensing position of the second fly eye lens element and the relay lens. And a diaphragm means capable of limiting an angle only in a horizontal direction of light from the lens element. 2. The relay lens limits an angle of a chief ray superimposedly irradiated by the cylindrical fly-eye lens element so as to be substantially parallel to an optical axis according to a viewing angle characteristic of the liquid crystal light valve. The projection-type image display device according to claim 1, wherein: 3. An elliptical reflector for condensing light emitted from a light source having a predetermined light emission range at an arbitrary position on an optical axis; a liquid crystal light valve for modulating light reflected by the elliptical reflector; and the elliptical reflector. And a liquid crystal light valve interposed between the first fly-eye lens element and the first fly-eye lens element, and divides the light only in the vertical direction reflected by the elliptical reflector into a plurality of pieces. A cylindrical fly-eye lens element configured to irradiate the liquid crystal light valve so as to overlap the entire liquid crystal light valve; and aperture means capable of limiting an angle only in a horizontal direction of light from the cylindrical fly-eye lens element; A cylinder lens that converts the principal ray of the luminous flux that has passed through the aperture means into parallel light parallel to the optical axis at an arbitrary position and irradiates the liquid crystal light valve with the light, Projection type image display apparatus characterized by being provided. 4. The cylinder lens according to the viewing angle characteristic of the liquid crystal light valve, converts the principal ray of the light beam that has passed through the aperture means into parallel light that is parallel to the optical axis in both the vertical and horizontal directions. The projection-type image display device according to claim 3, further comprising an aspheric lens for conversion. 5. An optional optic for increasing a peripheral light amount on a liquid crystal light valve by causing an arbitrary degree of pincushion distortion of light from the reflector between the reflector and the cylindrical fly-eye lens. 4. The projection type image display device according to claim 1, further comprising a conversion unit. 6. An elliptical reflector for condensing light emitted from a light source having a predetermined light emitting range at an arbitrary position on an optical axis, and converting light emitted from the elliptical reflector into parallel light substantially parallel to the optical axis. A condensing lens, a liquid crystal light valve for modulating light from the elliptical reflector, and a first fly light interposed between the condensing lens and the liquid crystal light valve for transmitting light only in a vertical direction from the condensing lens. The light is divided into a plurality of parts by an eye lens element, and the divided light is irradiated by being superimposed on the entire liquid crystal light valve by a second fly-eye lens element. The first fly-eye lens element and the second fly-eye lens element are each disposed at a light-condensing position of the first fly-eye lens element and the second fly-eye lens element; Projection display that the restrictor means only angle limiting horizontal direction of the light from the fly's eye lens elements, characterized by comprising a.