JP3330028B2 - Lighting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device used for a projection type liquid crystal display device, and more particularly to an illuminating device for converting the shape of a light beam condensed by a lamp reflector or the like into an outer shape of a rectangular display body. Things.

[0002]

2. Description of the Related Art A conventional illuminating device of this type is composed of only a lamp and a reflector, and a light source that reflects a light beam emitted from the lamp by a reflector is formed on a display such as a liquid crystal panel. The projected image on the screen.

In the case of a projection display device using such an illumination device, as shown in FIG. 9, since the outer shape of the display is rectangular, a part of the light beam in the shape of a lamp reflector is discarded. However, when this is projected on a screen, there is a problem that the projection screen becomes low in brightness.

As a method for solving this problem, for example, Japanese Patent Application Laid-Open No. Hei 5-346557 discloses a method in which a light beam in the shape of a lamp reflector is divided into rectangles similar to some display bodies using a lens array, and each image is displayed. A so-called fly-eye lens system in which a display body is illuminated with its outer shape by forming an image on the body has been proposed.

Japanese Patent Application Laid-Open No. 7-98479 discloses that
A so-called rod integrator system has been proposed in which a glass rod having a rectangular cross section is inserted into an optical system, and the image is formed on a display body to convert the shape of the lamp reflector into a rectangle.

[0006]

However, the fly-eye lens system proposed in JP-A-5-346557 requires not only a complicated lens configuration but also at least two lenses. Therefore, there is a problem that light loss due to reflection is large and the cost is further increased.

In the rod integrator system proposed in Japanese Patent Application Laid-Open No. 7-98479,
A large distance is required for the optical system, which leads to an increase in the size of the device. In addition, when the light source is not a point light source, light that cannot be incident on the glass rod is generated, and the light loss is also large.

The present invention has been made in view of such a point, and converts a light beam in the shape of a lamp reflector into a shape distribution of a rectangular display body with a simple configuration and causes the light flux to enter the display body. It is another object of the present invention to provide a lighting device capable of improving a light use efficiency and obtaining a bright projection screen.

[0009]

The illumination device of the present invention is provided with a quadrangular pyramid-shaped lens having a diamond-shaped bottom surface for converting a light beam emitted from a lamp and condensed by a reflector into a shape distribution of a rectangular display body. It becomes. The rhombus on the bottom surface of the quadrangular pyramid-shaped lens has a diagonal length ratio of width: length = b: a when the outer shape of the display body has a side: length = a: b side length ratio. I have.

With this configuration, the light flux in the shape of the lamp reflector can be converted into the shape distribution of the rectangular display body with a very simple configuration and can be incident on the display body, so that the light use efficiency can be improved. A bright projection screen can be obtained.

Further, in the above-mentioned quadrangular pyramid type lens, since the generatrix and the top of the quadrangular pyramid are flattened, light rays passing through the flattened portion are gathered near the center of the display. A uniform light flux distribution can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a lighting device according to the present invention will be described below with reference to FIGS. Here, FIG. 1 is an explanatory cross-sectional view of a main part showing a lighting device of the present embodiment,
Is a three-sided explanatory view showing a quadrangular pyramid-shaped lens in the illumination device of the present embodiment, FIG. 3 is an explanatory diagram showing a light beam cross section on the quadrangular pyramid-shaped lens in the illumination device of the present embodiment, and FIG. FIG. 5 is an explanatory diagram showing a light beam cross section on the display body surface of the device, FIG. 5 is an explanatory diagram showing ray tracing in the illumination device of the present embodiment, and FIG. 6 is an explanatory diagram showing light beam distribution on the display body surface in the illumination device of the present embodiment. It is.

First, in the following description, the optical axis direction of the optical system is defined as the z direction, and the vertical direction and the horizontal direction of the rectangular display body are defined as the y and x directions. In FIG. 1, 1 is a lamp, 2 is a reflector that reflects and condenses a light beam radially emitted from the lamp, and 3 is a glass pyramid lens that converts and condenses the light beam condensed by the reflector 2 into a rectangle. ,
Reference numeral 4 denotes a display body including a rectangular liquid crystal panel or the like having an aspect ratio of horizontal: vertical = a: b (hereinafter, a = 4, b = 3).

In the above configuration, the quadrangular pyramid lens 3 is
As shown in FIG. 2, a rhombus having a diagonal ratio of horizontal: vertical = 3: 4 has a bottom surface, and a light beam in the shape of a lamp reflector passing through this quadrangular pyramidal lens 3 is represented by an orthogonal rhombic diagonal line. As shown in FIG. The light beam divided into four becomes a fan-shaped figure (shaded portion in FIG. 3) having a right-angled apex angle, refracts and travels toward each vertex of the display 4. Then, on the display 4, as shown in FIG. 4, the apex angle becomes a rectangular corner portion, and the light is incident in a rectangular shape as a whole.

That is, since the diagonal lines of the rhombus on the bottom surface of the quadrangular pyramid-shaped lens 3 are orthogonal to each other, it is possible to divide the lamp reflector-shaped light beam into a fan shape having right-angled vertices at the center, and refract the light beam. By proceeding,
It can be converted to a rectangle having right-angled corners.

Further, the diagonal ratio of the bottom of the rhombus is defined as horizontal: vertical = 3:
By setting to 4, the ratio of the x component to the y component of the normal vector of the side surface of the quadrangular pyramid can be 4: 3,
The ratio between the x component and the y component of the traveling direction vector of the refracted light beam can be set to 4: 3. Thereby, the vertices of the fan-shape divided into four are respectively directed to the rectangular display body 4 of horizontal: vertical = 4: 3.

In designing the quadrangular pyramid-shaped lens 3, the inverse ratio of the aspect ratio of the display body 4 is adopted as it is to the diagonal ratio of the rhombus on the bottom surface, and the size is such that all the light flux in the shape of the lamp reflector can be taken. Then, the height of the apex of the pyramid is determined by ray tracing. Specifically, FIG.
As shown in (1), a ray of light passing through the apex of the quadrangular pyramid is traced, and it is determined that the ray reaches the corner of the display 4.

Assuming that a normal vector of one plane forming the side surface of the quadrangular pyramid is (L, M, N), a parallel ray (0, 0, 1) passing through the vertex of the quadrangular pyramid is incident on this plane. The direction vector of the refracted ray is

[0019]

(Equation 1)

## EQU1 ## Here, n is the refractive index of the quadrangular pyramidal lens 3, and L: M = 4: 3.

Further, when this ray is refracted in the second plane, its directional vector becomes

[0022]

(Equation 2)

## EQU2 ## By tracing this ray and determining (L, M, N) so as to reach the corner of the rectangular display 4 with a distance determined by the optical system, the height of the quadrangular pyramid-shaped lens 3 can be increased. You can decide.

In the illuminating device configured as described above, the light beam in the shape of the lamp reflector can be converted into the shape distribution of the display body 4 by the quadrangular pyramid lens 3. As shown in FIG. 6, the light use efficiency is improved and a bright projection screen is obtained as compared with the conventional lighting device (FIG. 9) in which the quadrangular pyramid-shaped lens 3 is not inserted.

Further, as a result of ray tracing by simulation with respect to the illuminating device of this embodiment, of the luminous flux emitted from the lamp 1, the luminous flux incident on the display 4 is 70.3.
%, And it is clear that the light use efficiency is remarkably improved as compared with 53.1% when the quadrangular pyramid type lens 3 is not provided.

Next, a device which realizes a more uniform light flux distribution in the first embodiment will be described as a second embodiment of the illuminating device of the present invention with reference to FIGS. 7 and 8. The same reference numerals are given to the same portions as the embodiment,
The description is omitted. Here, FIG. 7 is a three-sided explanatory view showing a quadrangular pyramid-shaped lens in the illumination device of the present embodiment, and FIG. 8 is an explanatory diagram showing a light flux distribution on a display body surface in the illumination device of the present embodiment.

The quadrangular pyramid type lens 13 in the present embodiment
As shown in FIG. 7, the quadrangular pyramid-shaped lens 3 of the first embodiment is formed such that the generatrix and the top of the quadrangular pyramid are flat.

When the quadrangular pyramid-shaped lens 13 of this embodiment is used, the light beam cross section becomes rectangular and enters the display 4 similarly to the first embodiment, but the flat section including the top of the quadrangular pyramid is used. Since the light beams passing through the portion are concentrated near the center on the display 4, it is possible to obtain a more uniform light flux distribution than in the first embodiment as shown in FIG.

Further, since the quadrangular pyramid lenses 3 and 13 in the above-described embodiment of the lighting device of the present invention do not include any complicated curves, they also have an advantage that they can be easily designed and manufactured.

[0030]

Illumination device according to the present onset light according to the present invention, since is provided a quadrangular pyramid type lens having a bottom surface of the rhombus which converts the light beam is condensed by the reflector is emitted from the lamp to the shape distribution of the rectangular display body With a very simple configuration, a light beam in the shape of a lamp reflector can be converted into a shape distribution of a rectangular display body and incident on the display body, thereby improving the light use efficiency and obtaining a bright projection screen. Becomes possible.

The illumination device according to the present onset Ming, the outer shape of the display is horizontal: vertical = a: If a side length ratio of b, and diamond bottom of the quadrangular pyramid type lens, a diagonal line of the length ratio Horizontal: Vertical = b: a
Therefore, it is possible to obtain a bright projection screen by further improving the light use efficiency according to the outer shape of the display body.

The illumination device according to the present onset Ming, since the flat pyramids of the bus portion and the top portion of the quadrangular pyramid type lens, it is possible to improve the uniformity of the light flux distribution on the display body .

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a main part showing a first embodiment of a lighting device of the present invention.

FIG. 2 is a three-sided explanatory view showing a quadrangular pyramid-shaped lens in the first embodiment of the illumination device of the present invention.

FIG. 3 is an explanatory diagram showing a light beam cross section on a quadrangular pyramid type lens in the first embodiment of the illumination device of the present invention.

FIG. 4 is an explanatory diagram showing a light beam cross section on a display body surface in the first embodiment of the illumination device of the present invention.

FIG. 5 is an explanatory diagram showing ray tracing in the first embodiment of the illumination device of the present invention.

FIG. 6 is an explanatory diagram illustrating a light flux distribution on a display body surface in the first embodiment of the illumination device of the present invention.

FIG. 7 is a three-sided explanatory view showing a quadrangular pyramid-shaped lens in a second embodiment of the illumination device of the present invention.

FIG. 8 is an explanatory diagram showing a light flux distribution on a display body surface in a second embodiment of the illumination device of the present invention.

FIG. 9 is an explanatory diagram showing a light flux distribution on a display body surface in a conventional lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lamp 2 Reflector 3, 13 Square pyramid lens 4 Display body

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03B 21/14 F21V 7/00 G02B 3/00 G02B 27/09

Claims (2)

(57) [Claims] 1. A lighting device for converging a light beam radially emitted from a lamp and making the light beam incident on a rectangular display body, comprising a diamond-shaped bottom surface for converting the collected light beam into a shape distribution of the display body. An illumination device provided with a quadrangular pyramid-shaped lens having a flat generatrix portion and a top portion . 2. The illumination device according to claim 1, wherein the rhombus on the bottom surface of the quadrangular pyramid-shaped lens has a lateral: vertical = a: b side length ratio when the external shape of the display body is: A lighting device, wherein the length ratio of the diagonal lines is set to horizontal: vertical = b: a.