DE10152800A1 - Lighting device, has projection display unit which modulates light from lighting device according to given image information via light valve - Google Patents

Abstract

A lighting device comprises a group of light sources with light source sections each formed from a luminous element or filament and a parabolic reflector. An integrator section is formed from at least two integrator plates in order to homogenize a light quanta emitted from the group of light sources in a section orthogonal to the optical axis, in which the integrated section is arranged in the direction of the optical axis. A parallel light flux-approximation-optical system is provided with a number of lens groups which largely correspond individually to the number of light source sections in the light source group. At least two lens groups are arranged downstream of the focal point in order to emit the light fluxes from the light-source group as a mainly parallel light flux to the integrator section. The first lens group forms a pair mainly parallel to one another and satisfies a Boolean expression Saxis Faxis, where Saxis is the distance between the optical axis of the complete lighting device and the optical axis of the light source section and Faxis is the spacing between the optical axis of the complete lighting device and the optical axis of the first lens group. An Independent claim is given for a projection display device.

Description

Field of the Invention

The present invention relates to a lighting device and a Projection display device, that of the lighting device emitted light according to predetermined image information by means of a Light valve modulated and the light thus modulated onto a screen projected; and in particular a configuration of a Illumination device comprising a plurality of light source sections having.

Description of the prior art

Conventional are methods that use a lens array or a lenticular plate use, known as an integrated lighting device, which in Projection display devices is used. Even with a light source uneven light distribution properties, such as one Metal halide lamp, a xenon lamp or a halogen lamp is used these methods can result in a lighting device that uneven lighting on the light valve due to the Can cancel light distribution properties of the light source.

Such a lighting device comprises a first integrator plate (commonly known as a second fly's eye or the like) and a second Integrator plate (commonly known as the first fly's eye or the like), the one after the other in this order downstream of a reflector using the light source section. The first integrator plate is by a plurality of two-dimensionally arranged lens elements formed, each of which is similar to the liquid crystal display board Has shape. A luminous flux emitted by the light source section with strong uneven brightness is caused by the first integrator plate in Partial luminous fluxes divided, the number of which with the number of lens elements first integrator plate is identical. The unevenness in the brightness the partial luminous flux is smaller than that of the undivided luminous flux. The Partial luminous fluxes form secondary light sources on the surface of the second integrator plate (the one with the pupil surface of a projection lens is conjugated) to the lighting area via the second Integrator plate and a field lens are emitted so that they overlap be, which results in lighting with a less uneven Brightness can be realized.

It is a projection display device, two of the above mentioned Integrator plates are used which are known to have a plurality of light sources which are arranged symmetrically around the optical axis, to ensure the amount of illuminating light, etc. (Japanese Patent Laid-Open No. 6-265887).

In the case of a lighting device with a single light source can the uneven lighting due to the light distribution characteristics of the light source by the integrator design mentioned above be eliminated. In a lighting device in which a plurality of light sources arranged symmetrically around the optical axis is, however, occurs due to the light distribution characteristics of the Light sources, a new intensity distribution. Because individual light sources, which each have different intensity distributions, a part occurs symmetrically around the optical axis with high intensity at a point that is not close to the optical axis but separated from the optical axis by a certain distance is on the pupil surface of the projection lens, which with the Surface of the second integrator plate is conjugated. However, that is Imaging performance of the projection lens near the optical axis is higher and gets smaller with increasing distance from it. If part with higher intensity, d. H. a part determining the imaging performance, such as mentioned above, is present at a location away from the optical axis the pupil surface is separated from a predetermined distance, it becomes more difficult, the projection lens own imaging performance completely exploit.

The applicant has already proposed the projection display device which is disclosed in Japanese Unexamined Patent Publication No. 11-44920 is as such that the problem mentioned above due to a Most light sources resolve. This projection display device is like this configured that the luminous flux from each light source section into one Integrator section are shifted to the optical axis of the Approach integrator section while the rate of change in distance from the center of the luminous flux to the optical axis the rate of change in Diameter of the luminous flux or larger. As a result, in the Pupil surface of the projection lens of the light spot caused by the luminous flux generated by each light source section at a location nearby the optical axis, which improves the imaging performance of the Projection lens can be made cheap.

In this conventional example, the luminous flux of each Light source section as mentioned above in the integrator section postponed. In particular, there are two wedge-like prisms in the Integrator section, or each of the lenses that make up the fly's eye is itself shaped into a wedge-like prism, making the above mentioned effects can be obtained.

SUMMARY OF THE INVENTION

In view of these circumstances, it is an object of the present invention in a configuration that is lower than traditional ones A lighting device is easier to assemble at a cost specify that the projection lens can cause its own Mapping performance fully achieved by the part with higher Light intensity corresponding to each light source closer to the optical axis the lighting device on the surface of the second integrator plate is arranged, which conjugates with the pupil surface of the projection lens, if a plurality of light sources are symmetrical about the optical axis is arranged around while the illuminating light through the Homogenizer type is homogenized.

Another object of the present invention is to provide a Specify projection display device that the above mentioned Has lighting device.

The present invention provides a lighting device comprising: a light source group in which a plurality of light source sections are arranged, each of which is composed of a luminous element and a reflector having a parabolic surface, in order to direct a luminous flux from the luminous element to a front side of an optical axis emit; an integrator section which is constructed from at least two integrator plates in order to homogenize a quantity of light emitted by the light source group in a cross section orthogonal to the optical axis, the integrator section being arranged in the direction of the optical axis; and a parallel luminous flux proximity optical system having a plurality of first lens groups which substantially individually correspond to the plurality of light source sections in the light source group and function to cause each of the light fluxes from the plurality of light source sections to be once a focal point; and at least one second lens group disposed downstream of the focus to emit the light fluxes from the light source group as a substantially parallel light flux to the integrator section; wherein the optical axis of the entire lighting device and optical axes of the light source section and the first lens group, which form a pair, are arranged substantially parallel to one another and satisfy the following Boolean expression (1):

Saxis> Faxis (1)

in which
Saxis is the distance between the optical axis of the entire lighting device and the optical axis of the light source section; and
Faxis is the distance between the optical axis of the entire lighting device and the optical axis of the first lens group.

At least one mirror element is preferably provided that is close at least one of those generated by the plurality of first lens groups Having a plurality of focal points has a reflective surface to reflect a luminous flux towards the second lens group.

The light source group preferably has two light source sections, while the mirror element that is close two through the first Lens groups created focal points on reflective surfaces has, is individually provided according to the light source sections.

Each of the at least one first lens group is preferred and at least a second lens group from a single lens with essentially the same shape. At least one of the first and second lens groups made from a single aspherical lens.

At least one second lens group is preferably integral with the Integrator plate on the light source group side in the integrator section formed on the surfaces of the light source group side.

The present invention provides a projection display device that the above-mentioned lighting device has a light valve for Modulating output light from the integrator section according to predetermined image information and a projection lens to a optical image formed by light modulated by the light valve to project a screen.

Here, the term "optical axis" referred to above refers entire lighting device and the optical axes of the Light source portion and the first lens group, which form a pair, are essentially parallel to each other "on the case where the optical Axis of the entire lighting device, the optical axis of the Light source section and the optical axis of the first lens group corresponding to the light source section substantially in parallel are in a state in which it is assumed that the Positions of the light source section and the first corresponding to it Lens group are arranged where the luminous flux from the Light source section runs straight through the first lens group so that he on the second lens group and the integrator section with removed Mirror element falls when the luminous flux from the light source section by inserting the mirror element toward the second lens group is distracted.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view showing the main part of the lighting device according to an embodiment of the present invention;

Fig. 2 is a schematic view showing the projection display device according to an embodiment of the present invention;

Fig. 3 is a schematic view showing the main part of the lighting device according to Example 1 of the present invention;

FIG. 4A is a schematic view showing the main part of the illumination device according to Example 2 of the present invention;

Fig. 4B is a schematic view of the part shown in Fig. 4A as seen from the second fly's eye;

Fig. 5A is a view showing an integral lens corresponding to the lighting device of Figs. 3, 4A and 4B; and

FIG. 5B is a view showing an integral lens corresponding to the lighting device of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention are explained with reference to the drawings. Fig. 2 is a view showing the configuration of the projection display device having the lighting device according to the present invention. This projection display device comprises an illumination device 10 according to the present invention and a projector section 20 which causes a luminous flux to be emitted by the illumination device 10 and converted into uniform light in order to take image information with it and to project it onto a screen. FIG. 1 is an enlarged view of part of the lighting device 10 shown in FIG. 2. The lighting device 10 will now be explained with reference to FIGS. 1 and 2. In the lighting device 10 , a parallel luminous flux emitted from its light source group 11 is shifted through a parallel luminous flux approximation optical system 12 to approach the optical axis of an integrator section 13 , that is, the optical axis X of the entire lighting device, and is then mixed in the integrator section 13 to homogenize the light quantity distribution.

Here, the light source group 11 comprises a plurality of (in this embodiment, two) light source sections 3 A, 3 B, which have luminous elements 2 A, 2 B, which are each formed from a discharge tube, such as a xenon lamp or a metal halide lamp, and reflectors 1 A, 1 B, which are each formed from a parabolic mirror, which are arranged symmetrically around the optical axis X of the lighting device 10 . The light emission source of the luminous elements 2 A, 2 B is arranged at the focal point of the reflector 1 A, 1 B, which is formed from a parabolic mirror. As a result, part of the luminous flux which is emitted by the luminous elements 2 A, 2 B to the rear and to the outside of the optical axis of the reflector 1 A, 1 B, ie the optical axis S _A , S _{B of} the light source section 3 A, 3 B , partially reflected as a luminous flux essentially parallel to the optical axis S _A , S _B.

The parallel luminous flux proximity optical system 12 includes a plurality of first lens groups 4 A (or 4 B, hereinafter similarly set in parentheses), which individually correspond to the light source sections 3 A ( 3 B) and have the function of causing the luminous flux of each light source section 3 A ( 3 B) once forms a focal point (secondary light source image); and a secondary lens group 5 A ( 5 B) which is arranged downstream of each focal point in order to emit the luminous flux from the light source section 3 A ( 3 B) as a substantially parallel luminous flux to the integrator section 13 . In Fig. 1, the second lens groups 5 A and 5 B are arranged so that they each point to the first lens groups 4 A and 4 B. The focal points f _A , f _B , which are formed by the second lens groups 5 A, 5 B and the first lens groups 4 A, 4 B, are namely on the optical axes F _A , F _{B of} the respective first lens groups 4 A, 4 B arranged.

In this embodiment, each of the first lens groups 4 A, 4 B and second lens groups 5 A, 5 B is formed from a single lens which has a positive refractive index, while all of these lenses are formed from aspherical lenses which have essentially the same shape. The shape of each aspherical surface is defined by the following aspherical surface expression. In Fig. 1, the aspherical surface of each of the first lenses 4 A, 4 B is aligned with the light source group 11 , while the aspherical surface of each of the second lenses 5 A, 5 B is aligned with the integrator section 13 .


in which
Z is the length of the orthogonal to a tangent plane (plane orthogonal to the optical axis) of an apex of the aspherical surface from a point on the aspherical surface with a height Y from the optical axis;
R is the paraxial radius of curvature of the aspherical surface;
Y is the height from the optical axis;
K is the eccentricity; and
A, B, C and D are fourth, sixth, eighth and tenth order aspherical surface coefficients.

The integrator section 13 has two integrator plates and a field lens 26 which are arranged in the direction of the optical axis X. The luminous flux from the parallel luminous flux proximity optical system 12 is divided into partial luminous fluxes by a second fly's eye 7 , the number of which is identical to the number of lens elements in the second fly's eye 7 , whereby tertiary light source images of the luminous elements 2 A, 2 B are formed on the individual lens elements that represent a second fly's eye 8 . These partial luminous fluxes are superimposed on a liquid crystal board 23 , which will be explained later, through the first fly eye 28 and the field lens 26 , as a result of which the amount of light is homogenized within a cross section of the illumination device orthogonal to the optical axis X.

Here, the light source group 11 , the parallel luminous flux approximation optical system 12 and the integrator section 13 are configured such that, for. B. the light source section 3 A meets the following condition. The optical axis 5 A of the light source section 3 A, the optical axis F _{A of} the first lens group 4 A, which forms a pair with the light source section 3 A, and the optical axis of the integrator section 13 , ie the optical axis X of the lighting device 10 , are namely essentially parallel to each other and satisfy the following Boolean expression (1 '):

S _A axis> F _A axis (1 ')

in which
S _A axis is the distance between the optical axis X of the entire lighting device and the optical axis S _{A of} the light source section 3 A; and
F _A axis is the distance between the optical axis X of the entire lighting device and the optical axis F _{A of} the first lens group 4 A.

If the above-mentioned conditions are met, the structure of the first lens group 4 A, through which the parallel light flux from the light source section 3 A once forms a focal point, and the second lens group 5 A, which is arranged downstream of the focal point, act emitting the luminous flux again as a substantially parallel luminous flux to the integrator section 13 is formed, according to this embodiment, in such a way that the output light from the light source section 3 A approaches the optical axis X in the parallel luminous flux proximity optical system 12 . The luminous flux from the light source section 3 B also satisfies the Boolean expression S _A axis> F _A axis as the Boolean expression (1 ') with respect to B, and the condition of parallelism between the individual optical axes, as a result of which it becomes the optical one Axis X can approximate as shown in FIG. 1.

From the figure, it can be seen that in this process, the parallel luminous flux from the light source section 3 A is transmitted through the parallel luminous flux proximity optical system 12 so that it approaches the optical axis X of the lighting device without changing the diameter of the parallel luminous flux. This process is similar to that performed in the integrator section in the above-mentioned conventional example proposed by the applicant, whereby similar effects can be obtained.

Namely, a part with higher intensity will be present on the first fly's eye 8 at a location separate from the optical axis X, because of the light distribution characteristics of the light source when the parallel luminous flux approaching the optical system 12 is not provided when a plurality of light source sections 3 A, 3 B are arranged symmetrically to one another around the optical axis in order to represent the lighting device 10 . When used as a projection display device, however, the imaging performance of the downstream projection lens 25 is higher near the optical axis and gradually decreases therefrom in all directions. Therefore, in order to effectively use the imaging performance of the projection lens 25 , it is desirable that a part with higher intensity be present at a position of the optical axis X on the pupil surface.

In this embodiment, essentially parallel luminous fluxes from a plurality of light source sections 3 A, 3 B are transmitted, so to speak, through the parallel luminous flux proximity optical system 12 in their respective directions, which approach the optical axis X, so that the part with higher intensity to positions near the optical axis X on the surface of the first fly's eye 8 (conjugated to the pupil surface of the projection lens 25 ). Since the higher intensity portion near the optical axis is collected on the pupil surface of the projection lens 25 as such, the imaging performance of the projection lens 25 can be made favorable.

These effects are substantially the same as those obtained with the projection display device disclosed in the above-mentioned Japanese Unexamined Patent Publication No. 11-44920. However, this conventional example achieves its effects using wedge-like prisms. In this embodiment, similar effects can be achieved by the parallel luminous flux proximity optical system 12 , which has at least two lenses with respect to a light source section, whereby the manufacturing costs of the elements can be greatly reduced compared to wedge-like prisms. Furthermore, the lens elements are easier to adjust compared to prism elements in view of the precision in assembling the device, whereby the productivity can be improved and the cost can be reduced.

Furthermore, it is desirable in the present invention that each of the at least one first lens group and the at least one second lens group is constructed from a single lens with essentially the same shape. For example, as mentioned above, all of the lenses 4 A, 4 B, 5 A, 5 B that constitute the parallel luminous flux proximity optics system 12 may be lenses that have substantially the same shape. The use of the lenses of substantially the same shape is advantageous in reducing the cost of manufacturing the elements. While the use of lenses with the same shape are unsuitable for all of these lenses when performance is more important, lenses with the same shape can give sufficiently satisfactory performance when considered in balance with cost. If the lenses 4 A, 4 B, 5 A, 5 B are provided with aspherical surfaces, the aberration corrections become favorable, whereby the lighting efficiency can be improved.

A projection display device with such an illumination device 10 will now be explained with reference to FIG. 2. As mentioned above, the luminous fluxes in which the amount of light is homogenized and the higher intensity part collects near the optical axis of the lighting device 10 fall on the projector section 20 . The projector section 20 comprises a B / GR separating dichroic mirror 21 for separating the luminous flux homogenized by the integrator section 14 into a B component LB and GR components LG, LR; a G / R separating dichroic mirror 22 for separating the GR components LG, LR output from the B / GR separating dichroic mirror 21 into a G component LG and an R component LR; a liquid crystal board 23 B for displaying an image for the B component; a liquid crystal board 23 G for displaying an image for the G component; a liquid crystal board 23 R for displaying an image for the R component; a three-color combination prism 24 for combining the luminous flux components LB, LG, LR which carry image information after having passed through the respective liquid crystal boards 23 B, 23 B, 23 R; and a projection lens 25 for throwing an image of the luminous fluxes composed by the three-color combination prism 24 onto a screen.

The projector section 20 further includes a total reflection mirror 27 through which the B component LB, which is emitted from the B / GR separating dichroic mirror 21 , is reflected toward the liquid crystal board 23 B; a field lens 28 B through which the B component LB, which is reflected by the totally reflecting mirror 27 , is converted into parallel light; a field lens 28 G through which the G component LG emitted from the G / R separating dichroic mirror 22 is converted into parallel light; totally reflecting mirrors 29 , 30 through which the R component LR, which is emitted by the G / R separating dichroic mirror 22 , is reflected towards the liquid crystal board 23 R; and a field lens 28 R through which the R component LR, which is emitted by the G / R separating dichroic mirror 22 , is converted into parallel light.

Although only the R component LR has a different optical path length to the three-color combination prism 24 in the projector section 20 , a field lens 31 is arranged between the G / R separating dichroic mirror 22 and the totally reflecting mirror 29 , and a transmission lens 32 is between the total reflecting mirrors 29 and 30 are arranged so that the field lens 31 and the transmission lens 32 correct the image of the R component LR, so that it appears to be identical to that of the B component LB and the G component LG. The three-color combination prism 24 is a cross prism with a dichroic surface 24 B for reflecting the B component LB and a dichroic surface 24 R for reflecting the R component LR.

As mentioned above, the lighting device 10 in the projection display device according to the present invention is configured such that a plurality of light source sections 3 A, 3 B are arranged symmetrically around the optical axis, while a part with higher intensity collects at a location that is closer to the optical axis X of the substantially parallel luminous flux which falls on the second fly's eye 7 . Therefore, on the pupil surface of the projection lens 25 in the projection display device which is conjugated with the surface of the first fly's eye 8 , the part with higher intensity near the optical axis collects, whereby a bright projection display device in which the projection lens 25 is one can be obtained has favorable imaging performance.

Examples

The above-mentioned illumination device 10 is configured such that in the parallel luminous flux approximation optical system 12, the luminous flux from the light source section 3 A, 3 B is caused to form 4 B once a focal point by the first lens group 4 A, and is the second lens group 5 A, 5 B is shifted such that it approaches the optical axis X as a substantially parallel luminous flux and is then emitted to the integrator section 13 . The following shows two examples of a lighting device that shows these effects. These lighting devices can also be used as the lighting device for the projection display device, as with the lighting device explained as the embodiment. In the following explanation, FIG. 2 can be used in view of the configuration of the entire lighting device and the projection display device. Also, in the following examples, elements whose names and functions are similar to those explained in the lighting device according to the above-mentioned embodiment are denoted by numbers identical to those of the embodiment without repeating the detailed explanation thereof.

example 1

The lighting device 10 according to Example 1 shown in FIG. 3 is configured such that a mirror element 6 for reflecting light flows to the second lens group 5 is arranged downstream of the first lens groups 4 A, 4 B. In this example, namely, the luminous fluxes from the light source sections 3 A, 3 B to the second lens group 5 are reflected by the mirror element 6 , which has reflecting surfaces 6 A, 6 B near the focal points f _A , f _B that pass through the first lens groups 4 A, 4 B are formed. The second lens group 5 is configured such that the two light fluxes from the first lens groups 4 A, 4 B are dropped onto the individual second lens group 5 , unlike in the lighting device mentioned above, in which the first lens groups 4 A, 4 B and the second lens groups 5 A, 5 B face each other.

In this example, each of the first lens groups 4 A, 4 B and second lens group 5 is constructed from a single lens with a positive refractive index, while all of these lenses are made from aspherical lenses with essentially the same shape. The shape of each aspherical surface is defined by the aspherical surface expression mentioned above. In Fig. 3, the aspherical surfaces of the first lens groups 4 A and 4 B are aligned with the light source section 11 , while the aspherical surface of the second lens group 5 is aligned with the second fly's eye 7 . The upper part of Table 1 shows the radius of curvature R (mm) of each lens surface, the center thickness D (mm) and the refractive index N _e on the e-line in each aspherical lens. In this table, the numbers with respect to each symbol gradually increase from the light source section side. The lower part of Table 1 shows the respective values of constants K, A, B, C and D of the aspherical surface, which are given in the above-mentioned aspherical surface shape expression. TABLE 1

In this example, too, the light source group 11 , the parallel luminous flux proximity optical system 12 and the integrator section 13 are configured to meet the following conditions with respect to the light source sections 3 A, 3 B. The optical axis S _{α of} a given light source section 3 α (where α is A or B), the optical axis F _{α of} the first lens group 4 α forming a pair with the light source section 3 α, and the optical axis of the integrator section 13 , ie The optical axis X of the lighting device 10 is namely essentially parallel to one another and satisfies the following Boolean expression (1 "):

S _α axis> F _α axis (1 ")

in which
S _α axis is the distance between the optical axis X of the entire lighting device and the optical axis S _{α of} the light source section 3 a; and
F _α axis is the distance between the optical axis X of the entire lighting device and the optical axis F _{α of} the first lens group 4 _α .

In FIG. 3, S _B axis and F _B axis are represented by dotted lines according to the position 3 B 'of the light source section and the position 4 B' of the first lens group, in the case in which the reflector surface 6 B is not arranged , Their values are of course constant regardless of whether the reflector surface 6 b is present or not. The Boolean expression (1 ") is preferably fulfilled not only for S _B axis and F _B axis in relation to the light source section 3 B shown in FIG. 3, but also for the light source section 3 A.

If these conditions are met, the structure acts from the first lens group 4 A ( 4 B), through which the parallel luminous flux from the light source section 3 A ( 3 B) forms a focal point, and the second lens group 5 , which is downstream of the focal point is arranged to emit the luminous flux again as a substantially parallel luminous flux towards the integrator 13 , also in this example in such a way that the output light from the light source section 3 A ( 3 B) of the optical axis X differs in the parallel luminous flux Approach optics system 12 approximates.

In particular, the mirror element 6 is used in this example, as a result of which the luminous fluxes from the light source sections 3 A, 3 B are dropped onto the second lens group 5 , while they are largely superimposed on one another, in comparison with the lighting device from FIG. 1. The parallel luminous flux thus emits Proximity optical system 12 a substantially parallel luminous flux in which a part with a higher intensity distribution is shifted by the light source sections 3 A, 3 B so that it further approximates the optical axis X of the second lens group 5 and the entire lighting device, as a result of which the Imaging performance of the projection lens 25 can be made even cheaper. Namely, it is desired that the individual elements of the light source sections 3 A, 3 B, the parallel luminous flux proximity optical system 12 and the mirror element 6 are arranged such that the part of the illuminating light with higher intensity is as close as possible to the optical axis X of the Illumination device is arranged on the pupil surface (which is conjugated with the surface of the first fly's eye 8 ) of the projection lens 25 .

If the light fluxes from a plurality of light source sections 3 A, 3 B that fall onto the second lens group 5 are largely superimposed on one another, as in this example, the second lens group 5 can be produced from at least one lens, so that the number of components is reduced can be reduced, which can reduce costs.

If, as in this embodiment, the mirror element 6 is used, both light flows from the light source sections 3 A, 3 B can be arranged closer to the optical axis X and fall on the second lens group 5 , in a state in which they are essentially superimposed on one another , As a result, a bright lighting device equipped with two light source portions that can cause the projection lens to fully display its imaging performance can be obtained by a configuration that can be easily assembled at a low cost.

If it is assumed that similar luminous fluxes are dropped onto the second lens group 5 without using the mirror element 6 , the light source section 3 A is arranged at a position which is around the optical axis X with respect to the position of the light source section 3 B ' , which is indicated by the dotted line, which is spatially difficult. This explains the effect of the mirror element 6 .

Example 2

FIGS. 4A and 4B show the illumination device 10 according to Example 2. Fig. 4A is a view of the lighting apparatus 10, viewed from the side, while FIG. 4B is a view of the lighting apparatus 10 as viewed from sides of the second fly's eye 7 here. This example is a lighting device which is provided with the mirror element 6 , as in Example 1, as a result of which the light fluxes from the light source sections 3 A, 3 B to the second lens group 5 are reflected by the mirror element 6, the reflection surfaces 6 A, 6 B near the focal points f _A , f _B , which are formed by the first lens groups 4 A, 4 B. The second lens group 5 is configured such that both light fluxes from the first lens groups 4 A, 4 B are dropped onto the individual second lens group 5 . The effects which are achieved by inserting the mirror element 6 are not explained here, since they are similar to those in Example 1.

In Example 2, each of the first lens groups 4 A, 4 B and the second lens group 5 is constructed from a single lens which has a positive refractive index, while these lenses are made from aspherical lenses with essentially the same shape. The shape of the aspherical surface and the orientations of the aspherical lenses are the same as those of Example 1 mentioned above.

In Example 2, the light source group 11 , the parallel luminous flux proximity optical system 12 and the integrator section 13 are configured to meet similar conditions as in Example 1 with respect to the light source sections 3 A, 3 B. If these conditions are met, the structure acts from the first lens group 4 A ( 4 B), through which the parallel luminous flux from the light source section 3 A ( 3 B) forms a focal point, and the second lens group 5 , which is downstream of the Focal point is arranged to in turn emit the luminous flux as a substantially parallel luminous flux towards the integrator 13 , also according to Example 2 such that the output light from the light source section 3 A ( 3 B) aligns itself with the optical axis X in the parallel luminous flux approximation. Optical system 12 approximates.

The lighting device of the present invention and the same Projection display devices using are not those of the above The examples mentioned are limited, but can in many ways be changed. For example, the configuration of each lens group and lens shape can be changed if necessary.

FIGS. 5A and 5B are enlarged views of the second lens group 5 and the second fly's eye 7 when they are formed integrally in the lighting device according to the present invention. In the lighting device of the present invention, the second lens group 5 and the second fly eye 7 downstream thereof may be an integrated lens 9 in which the second lens group 5 is integrally formed on the surface of the second fly eye 7 from the light source portion 11 as shown. FIG. 5A shows an example of the integrated lens corresponding to the lighting device of FIGS. 3, 4A and 4B, while FIG. 5B shows an example corresponding to the lighting device of FIG. 1. The manufacturing costs can be reduced if such an integrated lens 9 is produced by monolithic casting, e.g. B. using plastics. Furthermore, since there is no air gap between the lens of the second lens group 5 and the second fly's eye 7 , the lighting effect is better.

In the above-mentioned lighting device, the parallel light fluxes incident on the first lens groups 4 A, 4 B are emitted from the second lens groups 5 , 5 A, 5 B while being substantially the same diameter. Therefore, the lenses 4 A, 4 B, 5 , 5 A, 5 B can use lenses with the same shape. However, the configuration of the lighting device according to the present invention is not limited to this. The diameters of the light fluxes that fall on the first lens groups 4 A, 4 B and that of the substantially parallel light fluxes that are emitted by the second lens groups 5 , 5 A, 5 B can also be configured such that the latter are proportional are enlarged or reduced.

The number of light source sections in the lighting device according to the present invention is not limited to two, but any number that is not less than two can be selected. For example, as in the above-mentioned conventional example proposed by the applicant (Japanese Unexamined Patent Publication No. 11-44920), it may have four or nine light source sections. According to the present invention, although this conventional example is configured to shift a plurality of parallel luminous fluxes so as to approach the optical lighting device in the integrator section, the parallel luminous flux is shifted to approach the optical axis X before it falls on the integrator section 13 . Therefore, the light spot formed on the first fly eye (which is conjugated with the pupil surface of the projection lens) in the conventional example corresponds to the light spot formed on the second fly eye 7 in the present invention. Namely, according to the present invention, the size of the second fly's eye 7 can be made smaller than in the conventional example.

If the light spot that is caused by the luminous flux of one of a plurality is formed by light source sections on the optical axis X, it is not necessary for this light spot to position itself in relation to the optical axis X shifts, leaving this light source section free can be means for shifting the luminous flux.

The shape of the mirror element 6 used in the lighting device of the present invention is not limited to the above. Although it is desired that the mirror element 6 have reflective surfaces corresponding to the number of light source sections, it is not always necessary for the light fluxes from all of these light source sections to be reflected by the mirror element 6 in order to deflect their optical paths.

Although the above mentioned statements with regard to the Projection display device of the present invention explain where light after color separation and Color combination processes is projected is the present invention of course also applicable to a device for image projection in which neither a color separation nor a color combination process is carried out.

As explained above, the lighting device has the present invention, a parallel luminous flux proximity optical system, the plurality of first lens groups corresponding to a plurality of Light source sections and a second lens group that is located downstream of the focus through each first lens group is formed to be a luminous flux as essentially parallel Emit luminous flux toward the integrator section; while the optical axis of the entire lighting device and the optical Axes of the light source section and the first lens group, the one Form a pair, are substantially parallel to each other and the predetermined Boolean expression suffice. This makes it possible to a configuration that is easily assembled at a low cost can be to achieve a lighting device that the parallel Shift light fluxes from a plurality of light source sections can that each of these the optical axis of the Approaches lighting device and falls on the integrator section.

Since the projection display device of the present invention does the above Has mentioned lighting device, the part with larger Amount of light in the luminous flux emitted by the integrator section dropped the projection lens near its optical axis. Therefore, according to the present invention, a Projection display device that can cause the projection lens shows their full imaging performance, can be obtained in a configuration, that can be easily assembled at low cost.

A lighting device ( 10 ) comprises a light source group ( 11 ), a parallel luminous flux proximity optical system ( 12 ) and an integrator section ( 13 ). The light source group ( 11 ) comprises a plurality of light source sections ( 3 A, 3 B), which are constructed by reflectors ( 1 A, 1 B), each made from a parabolic mirror, and luminous elements ( 2 A, 2 B), which are on their Focal points are arranged. The parallel luminous flux proximity optical system ( 12 ) comprises first lens groups ( 4 A, 4 B) for causing light streams from the light source sections ( 3 A, 3 B) to form focal points (f _A , f _B ); and second lens groups ( 5 A, 5 B) which are arranged on their downstream side in order to emit the luminous fluxes as essentially parallel luminous fluxes towards a second fly's eye ( 7 ). The optical axis (X) of the entire lighting device ( 10 ), the optical axes (S _A , S _B ) of the light source sections ( 3 A, 3 B) and the optical axes (F _A , F _B ) of the first lens groups ( 4 A, 4 B) are substantially parallel to each other while they satisfy the Boolean expression Saxis> Faxis wherein Saxis is the distance between the optical axis of the entire lighting device and the optical axis of the light source portion (3 A, 3 B) and Faxis the distance between the optical axis of the entire lighting device and the optical axis of the first lens group ( 4 A, 4 B).

Claims (7)

A lighting device comprising:
a light source group in which a plurality of light source sections are arranged, each of which is composed of a luminous element and a reflector having a parabolic surface, in order to emit a luminous flux from the luminous element to a front side of an optical axis;
an integrator section which is constructed from at least two integrator plates in order to homogenize a quantity of light emitted by the light source group in a cross section orthogonal to the optical axis, the integrator section being arranged in the direction of the optical axis; and
a parallel luminous flux proximity optical system having a plurality of first lens groups which substantially individually correspond to the plurality of light source sections in the light source group and function to cause each of the light fluxes from the plurality of light source sections to be once a focal point; and
at least one second lens group disposed downstream of the focus to emit the light fluxes from the light source group as a substantially parallel light flux to the integrator section;
wherein the optical axis of the entire lighting device and optical axes of the light source section and the first lens group, which form a pair, are arranged substantially parallel to one another and satisfy the following Boolean expression (1):

Saxis> Faxis (1)

in which
Saxis is the distance between the optical axis of the entire lighting device and the optical axis of the light source section; and
Faxis is the distance between the optical axis of the entire lighting device and the optical axis of the first lens group. 2. Lighting device according to claim 1, wherein at least a mirror element is provided which is close to at least one that generated by the plurality of first lens groups Multiple focal points a reflective surface has a luminous flux to the second lens group to reflect. 3. Lighting device according to claim 2, wherein the Light source group has two light source sections; and where the mirror element that near two through the first lens group generated foci has reflective surfaces, individually is provided according to the light source sections. 4. Lighting device according to claim 1 or 2, wherein each of at least one of the first lens groups and the at least one second lens group is composed of a single lens, which in Have essentially the same shape. 5. Lighting device according to one of claims 1 to 3, wherein at least one of the first and second lens groups from one aspherical single lens is made. 6. Lighting device according to one of claims 1 to 4, wherein the at least one second lens group on the Light source group side in the integrator section at its Surface on the light source group side with the integrator plate is integrally formed. 7. A projection display device comprising a Lighting device according to one of claims 1 to 5 Light valve for modulating output light from Integrator section according to predetermined image information and a Projection lens to create an optical image through the light valve modulated light is formed to project onto a screen.