JPH05157986A - Illuminating optical device - Google Patents

Abstract

PURPOSE:To obtain an illuminating optical device by which the utilization efficiency of nearly parallel luminous flux being the luminous flux of a lamp reflected and projected by a reflector in a display body is enhanced. CONSTITUTION:This device is constituted of the lamp 1, the reflector 2, and an aspherical lens 3; and the lamp 1 is arranged nearly at the focusing position of the reflector 2 and the aspherical lens 3 which leads the luminous flux from the shape of the lamp and reflector to square shape is arranged ahead of the projecting side of the reflector 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical device used for a projection type display device and the like.

[0002]

2. Description of the Related Art Recently, a magnified projection display device has been attracting attention, which magnifies and projects a display image of a liquid crystal or the like on a screen to show a large screen.

This is because the screen display by a cathode ray tube (CRT) is naturally limited in size, and the size of the cathode ray tube itself becomes large in order to enlarge the screen, and the practical size is limited to about 40 inches. Therefore, this is to meet the demand for obtaining more images. Therefore, by using a liquid crystal or the like, the image displayed on this is projected on the screen,
There has been provided a display device capable of viewing an enlarged image. The illumination optical device used in this type of conventional projection display device is composed of only the lamp 8 and the reflector 9 as shown in the sectional view of FIG.
The light flux emitted from the reflector 9 is reflected by the reflector 9 to become a light flux, and the light flux is used as a light source to project the image of the display body 10 on the screen.

[0004]

However, in the above-mentioned prior art, since the light flux emitted from the lamp 8 is reflected by the reflector 9 and is emitted in the shape of a lamp reflector, this is used as a light source. In the projection display device described above, since the shape of the display body 10 is rectangular, a part of the light flux in the shape of the lamp reflector is discarded, and when this is projected on the screen, there is a problem that a dark image is formed. Was. Therefore, the present invention solves such a problem, and its purpose is to:
An illumination optical device that obtains a bright image by causing a substantially parallel light flux of a lamp reflector shape obtained by reflecting a light flux emitted from a lamp 8 by a reflector 9 into a square shape or a rectangular shape and making the light flux enter the display body 10 substantially in parallel is provided. It is in the place of providing.

[0005]

In the illumination optical apparatus according to the present invention, the light flux radially emitted from the lamp (1) is a reflector (2) or a light flux whose light flux is substantially parallel by a lens is used as a light source. ), The aspherical lens (3) that guides the cross-sectional shape of the light flux from the lamp reflector shape to, for example, a quadrangular shape is arranged in the space on the exit side of (1).

[0006]

【Example】

(Embodiment 1) As shown in FIG. 1, the lamp 1 is located at a substantially focal position of the reflector 2, and the light flux emitted from the lamp 1 is reflected by the reflector 2 and emitted from the reflector 2 in a cross-sectional shape. An aspherical lens 3 that leads from a reflector shape to a square shape is arranged. The shape of the aspherical lens 3 is shown in FIG.
As shown in, when considered in 1/8 of the reflector shape, the area of the area S ₁ of the incident side of the light emission side as shown in FIG. 6 S
₂ is S ₁ = π ÷ 8 × r ² S ₂ = 1/2 × a ² = r ² ÷ 4, where a = r ÷ √2. Therefore, the area compression ratio P from S ₁ to S ₂ is P = S ₂ ÷ S ₁ = 2 ÷ π. In addition, the area on the incident side is an area ΔS having an inclination of θ.
_{If the value is 1} , the area ΔS ₂ on the emission side is ΔS ₁ = 1/2 × r ² × θ ΔS ₂ = P × ΔS ₁ = 1/2 × a × b. Therefore, from the above equation, the relationship of b = 2 × √2 ÷ π × r × θ is obtained. That is, the slope ψ of the area of ΔS ₂ is tan ψ = b ÷ a = 4 ÷ π × θ. At this time, the coordinates of P and Q are P (r × cos θ, r × sin θ) Q (r ÷ √2, 2 × √2 ÷ π × θ × r). Further, from FIG. 5, the relation of r ′ = r ÷ √2 ÷ cosψ h ₁ = r−r ′ × cos (Δψ) h ₂ = r ′ × sin (Δψ) holds, and Δψ = ψ−θ Therefore, h ₁ and h ₂ are as follows: h ₁ = r {1−1 ÷ √2 × (cos θ + tan ψ × sin θ)} h ₂ = r ÷ √2 × (tan ψ × cos θ−sin θ)

[0007] In FIG 7, when we consider the incident and exit surfaces of the small area of the aspherical lens _{3, n 1 × sinβ 1 =} n 2 × sinβ 2 γ = β 1 over beta ₂ is satisfied. Therefore, from the above equation, β ₁ is β ₁ = Tan ⁻¹ {sinγ ÷ (cosγ−n ₁ ÷ n ₂ )}. Since there is a relation of tanγ = h ÷ l sinγ = h ÷ √ (l 2 + h 2) cosγ = l ÷ √ (l 2 + h 2), and substituting this into equation β _1, β ₁ = Tan ⁻¹ [h ÷ {l−n ₁ ÷ n ₂ × √ (l ² + h ² )}] is obtained. Therefore, the inclination of the lens surface in a small area can be calculated by ω = 90 + β ₁ . Further, the inclination of the lens surface has two components in the horizontal direction and the vertical direction, and has a refraction movement amount h ₁ in the vertical direction and a refraction movement amount h _{2 in the} horizontal direction. Therefore, β ₁ obtained by the refraction movement amount h ₁ is β ₁ (h ₁ ) = Tan ⁻¹ [h ₁ ÷ {l−n ₁ ÷ n ₂ × √ (l ² + h ₁ ² )}] Β ₁ obtained by the movement amount h ₂ is β ₁ (h ₂ ) = Tan ⁻¹ [h ₂ ÷ {l−n ₁ ÷ n ₂ × √ (l ² + h ₂ ² )}]. Therefore, the lens tilt ω according to h ₁ is ω (h ₁ ) = 90 + β ₁ (h ₁ ) and the lens tilt ω according to h ₂ is ω (h ₂ ) = 90 + β ₁ (h ₂ ). That is, the lens surface becomes a three-dimensional curved surface formed by ω (h ₁ ) and ω (h ₂ ) and becomes the aspherical lens 3 shown in FIG.

Therefore, the light flux emitted from the lamp 1 becomes the light flux of the lamp reflector shape shown in FIG. 10 by the reflector 2, enters the aspherical lens 3, and the light flux emitted by refraction in the lens is shown in FIG. It becomes a quadrangular light flux, passes through the display body 5, and enters the entrance pupil of the projection lens 6.

(Example 2) Aspherical lens 3 in FIG.
2 is replaced by the aspherical afocal lens 7 shown in FIG. 2, the lamp reflector-shaped light beam shown in FIG. 10 is converted into the rectangular light beam shown in FIG. 11 as in the first embodiment. The shape of the aspherical afocal lens 6 has a three-dimensional curved exit surface parallel to the entrance side, as shown in FIG.

Therefore, the light flux emitted from the lamp 1 becomes the light flux of the lamp reflector shape shown in FIG. 10 by the reflector 2, and enters the aspherical afocal lens 7.
The light beam emitted by refraction in the lens becomes a quadrangular substantially parallel light beam shown in FIG.

(Embodiment 3) In the aspherical lens 3 shown in FIG. 1 or the aspherical afocal lens 7 shown in FIG. 2, the light flux emitted from the lamp 1 is changed by the reflector 2 by changing each curvature in the orthogonal direction. The light flux entering the aspherical afocal lens 7 as a lamp reflector-shaped substantially parallel light beam shown in FIG. 10 and emitted by refraction in the lens becomes a substantially parallel light beam of the outer shape of the display body 5.

(Embodiment 4) As shown in FIG.
Like the above, the lamp 1 is at the substantially focal position of the reflector 2,
The aspherical afocal lens 7 is provided in front of the side where the light flux emitted from the lamp 1 is reflected by the reflector 2 and emitted.
Further, an anamorphic afocal lens 4 is arranged in front of the aspherical afocal lens 7 on the exit side to guide the cross section of the light flux from a rectangular shape to the outer shape of the display body 5.

As shown in FIG. 5, the light flux emitted from the lamp 1 is converted into a lamp reflector-shaped light flux shown in FIG.
The light flux that enters the lens and is emitted by refraction of the lens is
The quadrangular substantially parallel light flux shown in FIG. 1 is incident on the anamorphic afocal system lens 4 and emitted by refraction of the lens to be substantially parallel light flux of the outer shape of the display body 5. Therefore, the same luminous flux as that of the third embodiment can be obtained.

[0014]

As described above, according to the present invention, the luminous flux emitted from the lamp is reflected by the reflector and the luminous flux in the shape of the lamp reflector is passed through the aspherical lens to become a rectangular luminous flux. In addition, a light beam having the outer shape of the display body is obtained by passing the lens through the anamorphic afocal system. Thus, when an image of the display body is projected on the screen by using this light flux as a light source, a bright image is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an illumination optical device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an illumination optical device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an illumination optical device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of an illumination optical device according to a fourth embodiment of the present invention.

FIG. 5 is a shape diagram of 1/8 before and after an aspherical lens of parallel light flux in the present invention.

FIG. 6 is an explanatory diagram of area compression of an aspherical lens according to the present invention.

FIG. 7 is a sectional view illustrating refraction of the aspherical lens in the present invention.

FIG. 8 is a three-dimensional view of an aspherical lens according to the present invention.

FIG. 9 is a three-dimensional view of an aspherical afocal lens according to the present invention.

FIG. 10 is a view showing a shape of a lamp reflector.

FIG. 11 is a diagram showing a quadrangular shape.

FIG. 12 is a cross-sectional view of a conventional illumination optical device.

[Explanation of symbols]

 1 Lamp 2 Reflector 3 Aspherical Lens 4 Anamorphic Afocal Lens 5 Display 6 Projection Lens 7 Aspherical Afocal Lens 8 Lamp 9 Reflector 10 Display

Claims (4)

[Claims] 1. A cross-section of a light flux, which is a light flux in which a light flux radially emitted from a lamp (1) is made into a substantially parallel light flux by a reflector (2) or a lens as a light source, in a space on the exit side of the reflector (2). An illuminating optical device characterized in that an aspherical lens (3) for guiding the shape from a lamp reflector shape to, for example, a quadrangular shape is arranged. 2. The illumination optical apparatus according to claim 1, wherein the aspherical lens (3) is an aspherical afocal lens (6), and the lamp reflector shape is led into, for example, a quadrangular shape. 3. The aspherical afocal lens (6)
The illumination optical device according to claim 1 or 2, wherein the cross-sectional shape of the light flux is guided from the lamp reflector shape to the outer shape of the display body (5) by changing the respective curvatures in the orthogonal direction. 4. The aspherical afocal lens (6)
The illuminating optical device according to claim 1 or 2, wherein an anamorphic afocal lens (4) for guiding the cross-sectional shape of the light flux from a quadrangular shape to the outer shape of the display body (5) is arranged in front of the exit side of the.