JP3140164B2 - Focusing reflector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensing reflector used for various optical systems such as a liquid crystal projector, and more particularly to a condensing reflector for improving projection performance.

[0002]

2. Description of the Related Art Conventionally, there has been a light-collecting reflector of this type shown in FIGS. 9A and 9B. This figure 9
(A) and (B) show schematic configuration diagrams of a conventional condensing reflector, respectively.

[0003] In Fig. 9A, a conventional condensing reflector is formed by a reflecting mirror 2 having a paraboloid of revolution, and a light source 10 is disposed at a focal point F of the paraboloid of revolution. Is reflected by the reflecting mirror 2 having a paraboloid of revolution as parallel light.

The conventional light-collecting reflector shown in FIG. 9B is formed by a spheroidal reflecting mirror 3, and a light source 10 is arranged at a _first focal point F1 of the spheroidal surface. 10
Focused reflected to the rotation the second focal point F ₂ by the reflection mirror 3 of the ellipsoidal light from, is to emitted as parallel light by the condenser lens 42 to the focal point F ₂ of the second focus.

[0005] In each of the conventional condensing reflectors described above, a point light source 10 is disposed at the focal point F (or F ₁ ) of each reflecting mirror, so that a parallel light beam or a convergent light beam is emitted to produce an ideal circular projection surface or It can be reflected to an ideal point.

FIG. 10 is a schematic structural view of a conventional liquid crystal display device using a condensing reflector. In the figure, a conventional liquid crystal display device separates white light condensed and projected from a condensing reflector 100 into three colors of R, G, and B by dichroic mirrors 50 and 51, and separates each of R, G, and B light into a condenser lens. 81, the liquid crystal cells 60R, 60G, 60B
And the liquid crystal cells 60R, 60R according to each image signal.
G, 60B by changing the transmittance of the incident R, G,
Each color light of B is transmitted and blocked, and projected on a screen (not shown) via the projection lens 80. At this time, the white light of the condensing reflector 100 is parallel light, and the emitted light of FIGS. 9A and 9B is used.

[0007] As a light emitting source of each of the condensing reflectors,
There is a lamp that emits light between two electrodes, for example, a metal halide lamp known as high brightness and long life. FIG. 11A shows a schematic configuration of this metal halide lamp. Referring to FIG. 1, a metal halide lamp 10 includes two electrodes O ₁ and O ₂ arranged at a predetermined distance from each other.
2 and emit light in the arc tube 12 by discharging between the two electrodes O ₁ and O ₂ .

[0008]

In the lamp emitting light between the two electrodes, unevenness of color light occurs due to the difference in the light emitting area of the lamp itself. For example, in a lamp that emits light between two electrodes, such as the metal halide lamp, FIG.
As shown in FIG. 1 (A), white light having a very high temperature is generated in the light emitting region 15 in the central portion, and the light emitting region 1 in the outer peripheral portion is formed.
6 emits red light at a relatively low temperature. For this reason,
Irradiation surface 41 such as a screen by a conventional condensing reflector
Is irradiated with light from the lamp 10, the image of the light-emitting region having color unevenness is directly enlarged and projected on the irradiation surface 41, and as shown in FIG. 11B, the white projection unit 15a and the red projection unit 16a Therefore, there is a problem that the irradiation surface 41 cannot be irradiated with uniform color light. In particular, when a light-collecting reflector is used in a liquid crystal display device as shown in FIG. 10, there is a problem that a color image corresponding to an image signal cannot be obtained.

As a measure for reducing color unevenness on the irradiation surface 41, frost is applied to the transparent glass of the arc tube 12 to scatter uneven color light on the surface of the frost to make the color light uniform. You can also. However,
The frost arc tube has a problem that the size of the bulb itself becomes the size of the light source, cannot be a point light source (or a linear light source), and the light-collecting efficiency is reduced.

The present invention has been made in order to solve the above-mentioned problems, and has as its object to propose a light-collecting reflector that can irradiate an irradiation surface with uniform color light while maintaining a high light-collecting efficiency. I do.

[0011]

A condensing reflector according to the present invention is a condensing reflector for reflecting and irradiating light onto an irradiation surface 41, wherein an optical axis as the condensing reflector is used.
A first electrode O ₁ on the side far from the irradiation surface 41 ;
A second electrode O ₂ near side, but are spaced apart a predetermined distance, a light source 10 formed to surround the periphery of the two electrodes O _1, O ₂ in the transparent light-emitting tube 12, effective in the illuminated plane 41 The first reflection surface 20 having _one curvature CE1 with one end S ₁ of the irradiation area and the first electrode O ₁ as focal points, respectively.
If the the first reflecting surface 20 arranged adjacent to with each focal point and the other end S ₂ and the second electrode O ₂ facing to one end S ₁ of the effective irradiation region in the illumination plane 41, other curvature C
In which and a second reflecting surface 30 having a -E _2.

[0012]

In the present invention, the light-emitting device is housed in the transparent arc tube 12 and is disposed on the optical axis 1 in front of and behind the irradiation surface 41.
The _first and second elliptical reflecting portions each having the first electrode O ₁ and the second electrode O ₂ as one focal point are respectively combined, and each other focal point of the first and second elliptical reflecting portions is and then, is positioned at each end S ₁ and S ₂ of the effective irradiation region on the irradiated surface, in the effective exposure area, to reduce the difference in light intensity distribution by the color light difference, uniform color light Irradiate. In addition, since a point light source (linear light source) using a transparent arc tube is used, light collection efficiency can be maintained high.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A condenser reflector according to one embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of the light-collecting reflector of the present embodiment, and FIG. 2 is a detailed configuration diagram and an irradiation characteristic diagram of the light-collecting reflector of the present embodiment.

In each of the drawings, the light-collecting reflector according to the present embodiment emits transparent light from two electrodes O ₁ and O ₂ (coincident with the end points of the light source) which are arranged at an interval of 5 to 11 [mm]. A metal halide lamp 10 formed by coating with a tube 12 and one end S ₁ of an effective irradiation area on the irradiation surface 41 of the liquid crystal panel 4 to which light of the metal halide lamp 10 is irradiated and the one electrode O ₁ are focused. The first
Elliptic surface a first elliptical reflector portion 20 formed in the reflector body C-E _1, the outer peripheral end portion of the first elliptical reflector portion 20 C of
Are connected disposed adjacent, is formed by the second reflecting mirror of elliptic surface C-E ₂ to each focus and the other end S ₂ and the other electrode O ₂ of the effective irradiation region of the irradiation surface 41 And a second elliptical reflecting section 30.

The optical system of the condenser reflector of this embodiment is configured such that a line segment connecting two electrodes O ₁ and O ₂ of the metal halide lamp 10 is an optical axis 1. The liquid crystal panel 4
Are arranged in a plane perpendicular to the optical axis 1 and positioned so that the optical axis 1 passes through the center point S ₀ of the effective irradiation area in the liquid crystal panel 4.

Next, the operation of this embodiment based on the above configuration will be described.
explain about. First, the metal highland lamp 10
Electrode O₁, O_TwoAnd each ejected from the area in between
The light beam is emitted from the first elliptical curved surface CE of the first elliptical reflecting section 20.
₁At an arbitrary point P at the angle φ₁Incident on
Angle from any point P to ₁To illuminate the LCD panel 4.
Focus S on launch surface 41₁From the irradiation point S_TenIrradiated between
It is.

Further, each light beam emitted from each of the electrodes O ₁ and O ₂ and the region between them is applied to the second elliptical reflecting portion 3.
Incident at an angle phi ₂ between mutually Q any point in the second elliptic surface C-E ₂ 0, the focus S on the irradiated surface 41 of the liquid crystal panel 4 at an angle phi ₂ between each other from the arbitrary point is irradiated during the period from ₂ to irradiation point S _20.

That is, two different focal points (electrodes)
O _1, O ₂ of the first different curvatures of two to the focus of the primary, first, second respective elliptic reflecting portion 20 having a second respective elliptic surface of the _{C-E 1, C-E} 2, 30 are combined to form a reflector. In addition, the other focal points S ₁ and S _{2 of} the first and second elliptical curved surfaces CE ₁ and CE ₂ are the end points of the effective irradiation area on the liquid crystal panel 4. Since the focal points S ₁ and S ₂ are defined by the specific relationship with the liquid crystal panel 4 as described above, the internal white light and the external red light between the two electrodes O ₁ and O ₂ are separated by the liquid crystal panel 4. In the effective irradiation area of No. 4, irradiation is carried out after being averaged.

FIG. 2 shows an irradiation state in which the light intensity is averaged.
This will be described in detail with reference to the light intensity distribution-irradiation characteristic diagram of the liquid crystal panel position. In the figure, all the light emitted from the electrode O ₁ and reflected at an arbitrary point P of the _first elliptical curved surface CE ₁ is incident on the focal point S ₁ which is the upper end of the effective irradiation area of the liquid crystal panel 4. Light emitted from points other than the electrode O ₁ is mainly irradiated below the focal point S ₁ , resulting in a characteristic curve 200 (shown by a dashed line). In addition, all of the light emitted from the electrode O ₂ and reflected at an arbitrary point Q on the second elliptical curved surface CE ₂ is a focal point S ₂ which is the lower end of the effective irradiation area of the liquid crystal panel 4.
At the same time, light emitted from a point other than the electrode O ₂ is mainly irradiated above the focal point S ₂ , and the characteristic curve 30
0 (shown by a broken line ). Said first, Together each light issued input from the second of each elliptic surface _{C-E 1, C-E} 2, the light intensity distribution as the characteristic curve 100 (shown by a solid line) is effective radiation of the liquid crystal panel 4 It is averaged and illuminated in the area . Thus, the light intensity is averaged
It will be.

Furthermore, the irradiation state of the uniformed color light
3 is compared with the case of the prior art based on FIG.
explain. FIGS. 3A and 3B show the case where the focus is O.₁To be
Diagram of projection of parabolic mirror by conventional condensing reflector
4 (A) and (B) focus on O _TwoThe conventional parabolic mirror
FIG. 5 (A), (B)
Focus on O₁And O_TwoImplementation of combined elliptical reflector
It is a projection mode figure by an example.

[0021] FIG. 3 (A) shows a projection aspect view of a white light, light reflected from the region P-Q of the parabolic mirror in the drawing is substantially incident on the vicinity of the center So of the irradiated surface 41, the region QR
The reflected light from the light enters the peripheral portion of the irradiation surface 41. The reflected light from the region E ₁ -P of the parabolic mirror is not emitted, and the reflected light from the region RE ₂ is not irradiated onto the irradiation surface 41.
FIG. 3B shows a projection mode of the red light. The reflected light from the regions PQ and QR is applied to almost the entire irradiation surface 41. As described above, the red light with low light intensity is irradiated over the entire surface of the irradiation surface 41, whereas the white light with high light intensity is irradiated near the center So of the irradiation surface 41. 41 near the end S ₁
Red light is predominantly irradiated, and red is conspicuous
This results in uneven color .

FIG. 4A is a view showing the manner in which white light is projected. In FIG. 4A, reflected light from the region PR of the parabolic mirror is incident on the irradiation surface 41 from S ₃ to S ₁ . No reflected light is emitted from the region E ₁ -P, and no reflected light from the region RE ₂ is incident on the irradiation surface 41. FIG. 4B shows a projection mode of red light. In FIG. 4B, the reflected light from the region PQ of the parabolic mirror enters near the center So on the irradiation surface 41, and the region QR The reflected light from is incident on the peripheral portion on the irradiation surface 41. No reflected light is emitted from the region E ₁ -P, and the reflected light from the region RE ₂ is not irradiated onto the irradiation surface 41. Since red light is predominantly irradiated near the center So on the irradiation surface 41, color unevenness occurs.
You . Furthermore, since the reflected light from the region R-E ₂ is projected in addition to the irradiated surface 41, the light collection efficiency decreases.

In the case of the present embodiment shown in FIG. 5 with respect to the prior art shown in FIGS. 3 and 4, FIG.
(A), the light reflected from the region P-E ₂ of the ellipsoidal reflective surface mirror is incident on substantially all irradiated surface 41, primarily So the irradiation surface 41 the reflected light from the region P-C of this To S ₁ , and the reflected light from the region CE ₂ also enters the entire irradiation surface 41 from S ₁ to S ₂ . Further, FIG. 5 (B) shows the aspect of irradiating of the red light, the reflected light from the region P-E ₂ of the ellipsoidal reflective surface mirror in the figure incident on substantially all irradiated surface 41, the area P of the the reflected light from -C enters over the S ₁ of the irradiated surface 41 on the entire surface of S _2, light reflected from the region C-E ₂ is mainly S ₃ of the irradiated surface 41
And thus incident on the S ₄ from. As described above, a large amount of red light with low light intensity is irradiated near the center So on the irradiation surface 41 and a small amount of red light is irradiated near the periphery. Therefore, color unevenness can be greatly reduced. In addition, the light reflected from the region P-E ₂ from being incident on all the irradiated surface 41, it is possible to increase the light collection efficiency.

FIG. 6 shows a relative illuminance characteristic diagram of this embodiment, and FIG. 7 shows a conventional relative illuminance characteristic diagram. In this embodiment, the radius γ of the metal halide lamp 10 is 1.2 [mm].
, Ie, red light is condensed and emitted by the first and second elliptical reflecting portions 20 and 30 and irradiates the irradiation surface 41, resulting in a relative illuminance distribution as shown in FIG. In such a relative illuminance distribution, the red light is distributed over the entire effective irradiation area, which indicates that the effective irradiation area on the irradiation surface 41 is irradiated with uniform color light.

In the conventional relative illuminance characteristic diagram shown in FIG. 7 with respect to the present embodiment, the relative illuminance differs between the central portion and the outer peripheral portion in the effective illuminance distribution of the irradiation surface 41, and the red light is partially in Are distributed unevenly. That is, it indicates that color unevenness has occurred.

FIG. 8 shows an example of application of the light-collecting system to a liquid crystal projection TV. In FIG.
The light of the substantially uniform white light source emitted from each of the second elliptical reflecting portions 20 and 30 is converted into two dichroic mirrors 50 and 51.
The liquid crystal cells 60R and 60R are separated into three colors of R, G, and B, and the light transmittance changes according to the image signal of each of the RGB colors.
Images are formed by 0G and 60B, respectively. The respective formed images are synthesized again by the two dichroic mirrors 70 and 71, and projected onto a screen (not shown) by one projection lens 80.

Here, each liquid crystal cell 60R, 60R
If the G and 60B surfaces are positioned so as to be the irradiation surface 41, the light can be efficiently collected and uniform light of each color can be irradiated.

Further, each liquid crystal cell 60R,
If condenser lenses 81R, 81G, and 81B focusing on the incident position of the projection lens 80 are disposed on the light source side of 60G and 60B, the light use efficiency is further improved.

Also, by configuring the optical distances from the light source to the R, G, and B liquid crystal cells 60R, 60G, and 60B planes to be equal to each other, distortion of the combined output of the three colors of R, G, and B can be reduced. Disappears.

[0030]

As described above, according to the present invention, it is housed in a transparent arc tube and moves back and forth on the optical axis as viewed from the irradiation surface.
The first and second elliptical reflectors each having the first electrode and the second electrode arranged as one focal point are respectively combined, and the other focal points of the first and second elliptical reflectors are illuminated. Are arranged at the respective ends of the effective irradiation region, the effective irradiation region can be irradiated with an averaged light intensity distribution, and an effect that uniform color light can be irradiated can be achieved. In addition, since a point light source (linear light source) using a transparent arc tube is used, there is an effect that light collection efficiency can be maintained high.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a light-collecting reflector according to one embodiment of the present invention.

FIG. 2 is a detailed configuration diagram and an irradiation characteristic diagram of a condenser reflector in the embodiment shown in FIG.

FIG. 3 is a projection view of a parabolic mirror having a focal point of O ₁ by a conventional condensing reflector.

FIG. 4 is a projection view of a parabolic mirror having a focal point of O ₂ by a conventional condensing reflector.

FIG. 5 is a projection view of a combined elliptical reflecting mirror having focal points of O ₁ and O _{2 according} to the present embodiment.

FIG. 6 is a relative illuminance characteristic diagram in the example shown in FIG. 1;

FIG. 7 is a relative illuminance characteristic diagram in a conventional light-collecting lifter.

FIG. 8 is an overall configuration diagram when the light-collecting reflector shown in FIG. 1 is used in a liquid crystal display device.

FIG. 9 is a schematic diagram illustrating various configurations of a conventional light-collecting reflector.

FIG. 10 is an overall configuration diagram of a conventional liquid crystal display device.

FIG. 11 is a schematic configuration diagram of a general metal halide lamp and a condensing irradiation mode diagram of a conventional condensing reflector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical axis 2 ... 1st center line 3 ... 2nd center line 4 ... Liquid crystal panel 10 ... Metal halide lamp (light source) 12 ... Transparent luminous tube 20 ... 1st elliptical reflective part 30 ... 2nd elliptical reflective part 41 ... irradiation surface 50,51,70,71 ... dichroic mirrors 60R, 60G, 60B ... liquid crystal cell 80 ... projection lens 81R, 81G, 81B ... condenser lens O _1, O ₂ ... electrode (focus) S _1, S ₂ ... Each end point (focal point) of the effective irradiation area

Claims (1)

(57) [Claims] 1. A condensing reflector for reflecting and irradiating light onto an irradiation surface, wherein the condensing reflector is arranged on an optical axis as the condensing reflector from the irradiation surface.
A first electrode on the far side and a second electrode on the near side are arranged at a predetermined distance from each other, emit light between the two electrodes , and are formed by surrounding the periphery with a transparent arc tube; One end of an effective irradiation area on the surface and the first
As each focusing electrodes, and a first reflecting surface having a first curvature, disposed adjacent to said first reflecting surface, the other end portion opposite to the one end of the effective irradiation area of the irradiation surface and the second
Each and focus two electrodes, condensing reflector to feature in that it comprises a second reflecting surface having other curvature, the.