JPH07294920A - Projection type color display device and illumination device using it - Google Patents

Abstract

PURPOSE:To obtain a uniform, high-contrast and high-illuminance color projection display. CONSTITUTION:This is a projection type color display device provided with an elliptical mirror 12, a light source optical system provided with a light source at the first focusing position thereof and a convex conical prism 1 or a concave conical prism and a first diaphragm at the second focusing position, a color separation means 141, six condensing lenses of every RGB arranged at the optical path of color light, a transmission and diffusion type liquid crystal display element 15, a color synthesizing means 142, a second diaphragm 18 and a projection optical system 19. The light of the light source 11 whose directivity is arranged by the prism 1 is emitted as almost uniform luminous flux and efficiently made incident on the element 15. As a result, the utilizing efficienty of the light as the whole of the liquid crystal projector is drastically enhanced though it is compact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type color display device using a liquid crystal display element and an illuminating device using the same.

[0002]

2. Description of the Related Art White light emitted from a single light source is separated into three colors of R (red), G (green) and B (blue) by a dichroic mirror, and then three lights are provided for each color. 2. Description of the Related Art A projection type liquid crystal display device is known in which incident light is incident on a liquid crystal display element, emitted light is color-synthesized by a dichroic mirror, and then projected onto a screen using a single projection optical system.

A comparative example having the basic structure is shown in FIG.
Shown in. The color separation / combination optical system of this comparative example is, for example, “Proceeding of Japan Display 9
2, page 113 ".

Further, the light source optical system is provided with an elliptic mirror and a light source in the vicinity of the first focal point position, the directivity of the light source light is improved by using a diaphragm, and substantially parallel light is obtained by a condenser lens to transmit and scatter. Japanese Patent Application Laid-Open No. 4-113344 discloses a single-plate type projection display device which is made incident on a liquid crystal display element of a mold and further has a converging lens and a projection lens.

Further, a projection type display device in which a long rod type prism is arranged at the position of the diaphragm is disclosed in JP-A-4-142.
528. In these conventional examples, the light source light emitted from the light source optical system is first converted into substantially parallel light by a condenser lens and then incident on a dichroic mirror.

Next, a comparative example shown in FIG. 16 will be described. In this comparative example, an elliptic mirror 12, a light source 11, a diaphragm 17, a condenser lens (collimating lens) 731, and transmission / scattering type display elements 75R, 75G and 75B, and a dichroic mirror 141 constituting a color separation / combination optical system, 142, a projection optical system 20 having a projection lens, and the like.

Then, the light source 11 is arranged at the position of the first focal point of the elliptical mirror 12, the light from this light source 11 is condensed at the position of the second focal point, and the diaphragm 17 is arranged at the position of the second focal point. The light that has passed through the opening is condensed by the condenser lens 731, is converted into substantially parallel light, and the dichroic mirror 14 for color separation is used.
After being split into B, G, and R in 1, the light was made incident on the transmission / scattering type display elements 75B, 75G, and 75R corresponding to each color, and the non-scattered light of the transmitted light was provided for each display element. Condensing lens 732 (in the optical path position after the display element)
B, 732G, 732R collects the light on the projection lens of the projection optical system and dichroic mirror 1 for color combination
At 42, color composition is performed.

However, from the light source optical system to the liquid crystal display element 75
The uniformity of the intensity distribution of the light incident on B, 75G, and 75R and the projected light flux were still insufficient. This is because light that is blocked by the light-shielding portion of the light source 11 and forms an angle of about 10 ° or less with the optical axis at the second focal point is insufficient, and shade occurs near the center of the transmissive-scattering display element.

Further, when a projection type display device is constructed by using a transmission / scattering type liquid crystal display element as a display element, the contrast ratio of the projected image depends on the directivity of the incident light to the liquid crystal display element and the F number of the projection optical system. It is known that the higher the directivity of the light incident on the liquid crystal display element and the larger the F-number of the projection optical system, the higher the contrast ratio can be achieved (for example, “Proceeding of Japan”). Display 92, pages 113-116 ").

Since the light emitting portion of the lamp used as the light source is not an ideal point light source, in order to efficiently irradiate parallel light with high directivity on the surface of the liquid crystal display element, the light collecting portion having a relatively large focal length f. Requires a lens (mainly
When used as a collimating lens). A light source optical system having such a condenser lens as a component causes an increase in volume,
Therefore, there is a problem that the entire projection type display device becomes large.

[0011]

According to the present invention, a light source optical system for emitting light from a light source, a color separating means for separating the light from the light source into color light, a light collecting means for collecting the color light, and an external signal according to an external signal. It is composed of a transmissive scattering type display element having a different light scattering ability and provided for each color light, and a projection optical system for projecting color display light on a screen etc. by color-synthesizing each color light passing through the display element. In a projection type color display device, a light source optical system includes a light source, an elliptic mirror and a conical prism, and a condensing unit is in an optical path after the color separating unit and is on a light incident side of each display element. Or provided on at least one of the light emitting side,
There is provided a first projection type color display device, characterized in that the color light in the optical path from the color separating means to the light collecting means is non-parallel light.

Further, in the above-mentioned first projection type color display device, the light source optical system is provided with a light source, an elliptic mirror, a spherical mirror and a conical prism, and the light source is located near the position of the first focal point of the elliptic mirror. , A cone-shaped reflector near the position of the second focal point of the elliptic mirror, and a spherical mirror having a curvature center near the position of the first focal point of the elliptic mirror, respectively. The depth H of the elliptic mirror and the first focal length f ₁ And K = H / f ₁ is 1 to 1.3, and the reflecting surface of the spherical mirror covers the first focal point side of the elliptic mirror from the second focal point side and has an opening on the second focal point side. A second projection type color display device is provided.

Further, in the above-mentioned first or second projection type color display device, the first condenser means arranged on the light incident side of the display element and the second condenser means arranged on the light emitting side of the display element. A third projection-type color display device is provided which is provided with the light collecting means.

Further, in the above-mentioned first or second projection type color display device, there is provided a fourth projection type color display device characterized in that the light condensing means is arranged on the light incident side of the display element. To do.

Further, in the projection type color display device according to any one of the first to fourth aspects, a first diaphragm is provided at a position between the cone-shaped prism and the color separation means. A fifth projection-type color display device is provided.

In the projection color display device according to any one of the first to fifth aspects, the image of the cone-shaped prism or the first diaphragm is substantially formed at the position where the image is formed by the light converging means. A sixth projection type color display device is provided in which a second diaphragm having an opening of the same shape is arranged.

In the projection color display device according to any one of the first to sixth aspects, a liquid crystal display element is used as a display element, and a nematic liquid crystal having a positive dielectric anisotropy is provided between the substrates with electrodes. Has a liquid crystal solidified substance complex dispersed and held in a solidified substance matrix, and the refractive index of the solidified substance matrix is used to be either the ordinary light refractive index (n ₀ ) or the extraordinary light refractive index (n _E ) A seventh projection type color display device is provided, which is a liquid crystal display element matched with one side.

Further, a light source optical system for emitting a light source light, a color separation means for color-separating the light source light into color light, a light condensing means for condensing the color light, and a light scattering ability which changes according to an external signal so that the respective color lights are changed. Each of them is composed of a transmission / scattering type display element, a color separation means for color-synthesizing the respective color lights passing through the display element, and a projection optical system for projecting the color-synthesized color display light on a screen or the like. A projection type color display device, wherein a light source optical system includes a light source, an elliptic mirror or a composite collecting mirror, and a conical prism, and the condensing means is in an optical path after the color separating means, and is a display element. Eighth projection type color, which is provided on each of the light incident side and the light emitting side, and the colored light in the optical path from the color separation means to the light condensing means on the light incident side is non-parallel light. A display device is provided.

In the projection color display device according to any one of the first to eighth aspects, the apex angle α of the convex cone prism is 100 ° to 150 °, or the apex angle of the concave cone prism. A ninth projection type color display device is provided in which β is set to 210 ° to 260 °.

In the projection color display device according to any one of the above first to ninth aspects, the light condensing means includes the first light condensing means arranged on the light incident side of the display element and the display element. A tenth projection-type color display comprising: a second condensing unit arranged on the light emission side and condensing the transmitted light from the display element at the pupil position of the projection lens in the projection optical system. Provide a device.

Further, there is provided an illuminating device characterized by using any one of the above-mentioned projection type color display devices.

Further, the first focal length of the elliptical mirror 12 is F ₁
And the second focal length is F ₂ (F ₂ > F ₁ ), and the lengths of the light emitting portions of the light source 11 in the directions parallel and perpendicular to the axis of rotational symmetry of the elliptic mirror 12 are R and S, respectively. The vertexes of the cones (convex cone-shaped prisms or concave cone-shaped prisms) are parallel to the rotational symmetry axis of the elliptic mirror 12 and the distances to the second focus in the vertical direction, respectively.
A first light source optical system in which R and ΔS are ΔR ≦ 0.25 × R × (F ₂ / F ₁ ) ² and ΔS ≦ 0.5 × S × (F ₂ / F ₁ ). provide.

In this first light source optical system, the length R of the light emitting portion of the light source 11 and the effective area S _{A of} the cone on the light incident side are 0.2 mm ≦ R ≦ 10 mm, and
0.2 × (R × F ₂ / F ₁ ) ² ≦ S _A ≦ 0.8 × (F ₂
The second light source optical system is characterized in that xF ₁ ). In practice, many light source lamps in the range of 1 mm ≦ R ≦ 7 mm can be used. Then, the image generation optical system of the above-mentioned projection type color display device (systems after the color separation means)
Various projection type color display devices are provided in combination with the above. The present invention will be described below.

FIG. 13 shows a sectional view along the optical axis of the light source optical system used in the present invention. This light source optical system includes an elliptical mirror 12
It has a light source 11 and a convex cone-shaped prism 1 or a concave cone-shaped prism 2 described later. The convex conical prism 1 has a convex apex angle of 100 ° to 150 ° in the cross section, and the concave conical prism 2 has a concave apex angle of 210 ° to 260 °. That is, it has a convex or concave truncated cone shape or a truncated pyramid shape (including a polygonal pyramid and the like in addition to a quadrangular truncated pyramid shape).

The convex or concave cone-shaped prism is arranged in the vicinity of the second focal position of the elliptical mirror 12 (F _{2 in the} figure).
Means the second focal length of the elliptical mirror), but in the case of a convex cone-shaped prism, its apex is the second focal length.
It is preferable that the apex of the concave cone prism is located on the side opposite to the ellipsoidal mirror with respect to the focal point position, and the apex thereof is within the distance of about the light emission length of the light source or closer to the elliptic mirror side with respect to the second focal point position. Strictly speaking, the light distribution of the light source 11 and the first elliptic mirror
The optimum position is determined by the positional relationship between the focal point and the light emitting portion of the light source. In this figure, light enters from the flat bottom surface side of the conical prism and exits from the conical surface side. FIG. 5 shows an optical path diagram in the vicinity of the conical prism. In FIG. 5, two light beams (incident light A and incident light B) are incident on the conical prism at an incident angle γ,
This is schematically shown as outgoing light C that is substantially diffused from the conical surface.

As described above, the apex of the cone-shaped prism is usually arranged on the light emitting surface side, but in some cases, it is effective even if it is arranged on the light incident side. The light emitting portion of the light source 11 is not an ideal point light source but has a finite length,
The light emitted from 1a lacks the luminous flux in the vicinity of the optical axis, and it is difficult to obtain the uniformity even if the light is converged to the second focal position by the elliptical mirror. As shown in this figure, it is shown that the light flux is incident on the cone (pyramidal prism) as a nonuniform light flux, and the incident light flux within the incidence angle γ is insufficient. Reference numeral D ₁ shown in FIG. 13 is a diameter that allows for the effective exit surface size of the light source 11 from the second focus.

Next, the shape and the angle of the convex cone-shaped prism 1 or the concave cone-shaped prism 2 of the cones used in the present invention will be described with reference to FIG.

The actual cone-shaped prism is a three-dimensional structure, but the light travels in a plane including the central axis of rotation of the cone-shaped prism (usually, approximately coincides with the optical axis of the projection display device). You should think about. FIG. 12 shows a state in which light is incident on the prism body from the left side, is refracted by the incident surface and the exit surface, and is transmitted and emitted. In this case, the incident light with the incident angle ω is refracted by the prism body and transmitted, and then travels along the optical path pt. As an example, it is assumed that the optical path pt is parallel to the optical axis.

In FIG. 12 and the following equations,
ω: incident angle to the prism body, x: refraction angle on the incident surface side,
y: incident angle inside the prism with respect to the emission surface on the emission surface side, α: apex angle of the convex portion (the bisector of α is parallel to the optical axis and ideally coincides with it), β: Vertical angle of the recess (α + β
= 360 °. ), N _P : Indicates the refractive index of the conical prism.

According to Snell's law and the like, the equation 1 is obtained, and the equation 2 is established.

[0031]

[Number 1] _{sin (ω) = n P ·} sin (x) sin (90 ° -α / 2) = n P · sin (y) x + y = 90 ° -α / 2 cos (α / 2) = n P _{· sin (y) = n P} · sin (90 ° -α / 2-x) = n P · cos (α / 2 + x) = n P · cos (α / 2) · cos (x) -n P · sin (Α / 2) · sin (x) = [(n _P ² −n _P ² · sin ² (x)) ^1/2 ] · cos (α / 2) −sin (α / 2) · sin (ω) = [(N _P ² −sin ² (ω)) ^1/2 ] · cos (α / 2) −sin (α / 2) · sin (ω) (1 + sin (ω) · tan (α / 2)) ^{2 _{= n P 2 -sin 2 (ω}} ) sin 2 (ω) · tan 2 (α / 2) +2 · sin (ω) · tan (α / 2) + 1 + sin 2 (ω) -n P 2 = 0

[0032]

Tan (α / 2) = [(n _P ² −sin ² (ω)) ^1/2 −1] / sin (ω)

In this equation 2, the physical characteristic value is determined by the material used. When the materials used were borosilicate glass and plastic (refractive index of about 1.5) and flint glass (refractive index of about 1.8), the above-mentioned angle range was obtained by calculation. α indicates the apex angle of the convex portion of the prism body. β represents the angle of the apex angle of the concave portion of the prism body. In the present invention, the refractive index of the prism body is more preferably in the range of 1.45 to 1.65.

In the configuration of the light source optical system of the present invention, the elliptical mirror 12 is used.
Is used as a reflecting and converging means, the light source 11 is provided at the first focal point thereof, and the light converged by the reflecting surface of the elliptic mirror 12 and condensed at the position of the second focal point is shaped like a cone. It is incident on the prism. In this case, as shown in FIG.
There is a relation of the following equation 3, and the diameter of the arc tube of a practical light source is 1
Since it is 0 to 30 mm, the D ₁ value shown in this figure is also in an approximate range. Therefore, in the light distribution of the incident light on the cone, a region having an angle γ or less with the optical axis where no light exists is described by the mathematical expression 3.

[0035]

[Equation 3] tan (γ) = D ₁ / (2 · F ₂ )

The second focal length F ₂ of the practical elliptical mirror 12 is about 50 to 200 mm. Therefore, from Equation 3, γ is approximately 3 ° to 30 °. In practical terms,
It is preferable to keep the value of γ small, and D ₁ = 3
Γ = 3 determined by the combination of 0 mm and F ₂ = 50 mm
The case of 0 ° is not practical.

Then, with ω = γ, the value of the apex angle α of the convex cone prism 1 is the numerical aperture of the condenser lens (lens diameter / lens diameter /
When the focal length is 0.2 to 0.8, 90 ° to 17
When using a condenser lens with 5 ° and a numerical aperture of 0.2 to 0.5, the range of 100 ° to 150 ° is preferable.

In the case of the concave cone prism 2, similarly, a condenser lens having a numerical aperture of 185 ° to 270 ° and a numerical aperture of 0.2 to 0.5 is used in the range of 0.2 to 0.8. 21 if there was
The range of 0 ° to 260 ° is preferable. Here, the case where the light emitted from the conical prism is parallel to the optical axis has been described, but any prism shape in which the incident light is refracted so as to compensate for the lack of the luminous flux distribution near the optical axis may be used. .

Here, the basic optical configuration of the present invention will be described with reference to FIG. The directivity of the incident light on the display element is defined as the dispersion angle ζ by the equation 4.

[0040]

## EQU4 ## tan (ζ) ≈D ₂ / L ₁

Here, D ₂ is the average diameter of the first aperture stop 17 provided at the second focal position of the elliptic mirror, and in the figure, L ₁ is the condenser lens (first condenser means 131). The value is almost equal to the focal length. Of the transmitted light of the display element, the light projected on the screen is directional light up to the converging angle η defined by Equation 5.

[0042]

[Equation 5] tan (η) ≈D ₃ / L ₂

Here, D ₃ is the average diameter of the second diaphragm 18 provided at the focal position of the condenser lens (field lens or the second condensing means 132), and L ₂ is its focal length. . In the optical system arranged as described above,
The collection angle η is preferably set to be substantially equal to the above dispersion angle ζ.

Further, the converging angle η in the projection type liquid crystal display device using the liquid crystal optical element having the transmission / scattering mode.
FIG. 14 shows (η≈ζ) and the contrast ratio of the light projected on the screen. The display element is a liquid crystal optical element having a liquid crystal solidified substance composite, which will be described later, as a functional layer, and the driving voltage thereof is 6V. In this case, the drive is based on a rectangular wave and indicates the amplitude value thereof.

Then, the second that occurs when an elliptical mirror is used
The non-uniformity of the in-plane light intensity distribution of the display element due to the lack of a light component having a small angle formed by the optical axis at the focal position is apex angle α100 depending on the shape of the light source and the elliptic mirror and the display area of the display element. By using a convex-cone prism having a degree of 150 ° to 150 ° or a concave-cone prism having an apex angle β of 210 ° to 260 °, the problems are improved and uniformized. From the viewpoint of light use efficiency and brightness distribution on the projection screen, it is more preferable that the vicinity of the center of each of the above-mentioned angular ranges is good. Further, it is more preferable that the plurality of separated light beams on the incident surface side are densely folded on the emission surface side.

It is preferable that 60% or more of the light beams overlap in a cross section parallel to a plane whose normal is the optical axis. Furthermore, since only the light that has passed through the conical surface of these cones and the first diaphragm is incident on the display element, the directivity of the light flux is extremely uniform. Then, the second diaphragm, which is a means for removing scattered light, can efficiently remove scattered light from the transmitted light that has passed through the transmissive-scattering type display element, and a projected image with a high contrast ratio can be obtained.

Further, in the present invention, the light distribution of the light beam incident on the condenser lens 13 can be adjusted according to the apex angle of the conical object placed at the second focus position of the elliptical mirror 12, so that the display element Even when 15 is a non-square shape, light can be effectively condensed on the display element surface.

For example, for NTSC with an aspect ratio of 3: 4 and HDTV with 9:16, in the cross section of the prism including the optical axis, when the convex cone prism 1 is used, the vertical apex angle is horizontal. The angle is smaller than the apex angle in the direction (longitudinal direction). For example, when the concave cone prism 2 is used, the optical axis is set so that the vertical apex angle is larger than the horizontal apex angle. This is possible by using a prism whose shape in a vertical cross section is elliptical or rectangular.

At this time, in order to prevent light reaching other than the effective transmitting surface of the convex or concave cone-shaped prism from reaching the condenser lens, in the vicinity of the second focal position of the elliptic mirror 12,
It is preferable to provide the first diaphragm 17 between the conical prism and the condenser lens.

This makes it possible to remove the light components not condensed near the second focal point by the light source of the finite length and the elliptic mirror, and to make the light flux uniform, and reach the screen when the transmission / scattering type display element is in the scattering state. Unnecessary light can be reduced and the contrast ratio can be improved.

Furthermore, between the display element and the screen,
It is more effective to provide a means for removing scattered light, specifically, the second diaphragm 18.

At this time, the opening area of the first diaphragm 17 and
A second diaphragm 18 installed as a means for removing scattered light
The aperture area is variable, and for example, when the surroundings are dark, the influence of light from the surroundings on the screen is small and the dark spots on the projected image can be identified, so the amount of light passing through can be reduced by narrowing down the two diaphragms. Alternatively, the contrast ratio can be adjusted so as to be high, and a display image having a high contrast ratio and brightness that is easy to see can be obtained.

On the contrary, when the surroundings are bright, the light from the surroundings is reflected on the screen, and the dark portion of the projection image by the projection type display device looks bright to some extent.
At this time, by opening the two diaphragms to increase the amount of projection light and brighten the screen, a high contrast ratio can be obtained, and it is possible to make it easier to see. In this way, the optimum projection image is obtained according to the surrounding brightness environment by interlocking the two apertures.

Since a condenser lens is provided on at least one of the light incident side and the light emission side of each of the three liquid crystal display elements, a single condenser lens arranged on the light source optical system side is used for color separation. Compared with the configuration of the comparative example shown in FIG. 16 in which parallel light is made before entering the system, the light source optical system is downsized and a condenser lens having a relatively long focal length is used. The volume is reduced and it is easy to obtain parallel light with high directivity.

2 and 3 show ray trajectories in the case of the convex cone-shaped prism 1 and the concave cone-shaped prism 2. The light emitted from the elliptical mirror is refracted by the conical prism to generate an azimuth light component near the optical axis and also functions to increase the luminous flux density.

Next, the reflection converging means of the light source optical system will be described. Compared with the case where one elliptic mirror 12 is used as the condenser mirror of the light source optical system, the elliptic mirror 12A as shown in FIG.
And a spherical mirror 12B are combined to form a compound condensing mirror, so that light having uniform directivity can be efficiently condensed by the condensing lens 131.
The light can be condensed on the effective surface of B, 131G, and 131R. At this time, the depth H of the reflecting surface of the elliptical mirror 12A is shallower than that shown in FIGS. 2 and 3, and the ratio K = H / F ₁ with the first focal length F ₁ is ₁ to 1.3. It is preferable to set the degree.

The spherical mirror 12B is the first of the elliptical mirrors 12A.
The center of curvature is in the vicinity of the focal point and its reflecting surface is an elliptical mirror 1.
2A covers the second focus direction side from the first focus of 2A
It is configured to have an opening on the focal direction side. The arrangement configuration relationship with the cone-shaped prism is almost the same in FIGS. 2 and 3.

[0058]

In the projection type display device of the present invention, particularly the projection type color display device, the dispersion angle φ (or ζ) representing the directivity of the light emitted from the light source optical system and incident on the display element is a cone of the light source optical system. The diameter D ₂ of the effective transmission surface of the body prism or the light emission surface defined by the first diaphragm 17 and the distance from the light emission surface to the condenser lens 13 or from the light emission surface to the liquid crystal display element 15 The shorter of the distances L
Approximately 6 is described by using ₁ .

[0059]

[Equation 6] tan (φ) = D ₂ / L ₁

9 to 11 show ζ in various configurations,
φ, D ₂ , and L ₁ are illustrated. At this time, the light exit surface of the light source optical system does not necessarily have to be circular, and may have a shape such as a rectangle or an ellipse. In that case, the diameter D ₂ corresponds to the average diameter.

Therefore, the dispersion angle φ of the light incident on the display element becomes smaller as the diameter D ₂ of the light emitting surface becomes smaller or the distance L becomes smaller.
_The larger ₁ is, the smaller the light is and the more directivity the light becomes. However, in general, the smaller the diameter D ₂ of the light emitting surface, the smaller the proportion of the emitted light from the light source that can emit the inner diameter D ₂ . Further, as the distance L ₁ increases, the luminous flux density decreases, so that the luminous flux incident on the display element having the same display area decreases.

Therefore, in order to efficiently generate light with high directivity and to form a projection image having a uniform intensity distribution, the shape of the elliptical mirror 12 and the cone-shaped prism, which are the constituent elements of the light source optical system, are formed. There is a favorable relationship between the shape and the display area of the display element and the focal length of the condenser lens.

The divergence angle φ of the incident light on the liquid crystal display element is determined at an appropriate angle depending on the required contrast ratio of the screen projection image and the scattering ability of the transmission / scattering type display element. Dispersion angle of 10 ° or less when the contrast ratio is 50 or more phi, be selected D ₂ and L ₁ defined by Equation 6 as contrast ratio as a phi dispersion angle of 7 ° or less in the case of more than 100 preferable.

Further, in order not to increase the size of the light source optical system, the ratio F between the second focal length F ₂ of the elliptic mirror and the first focal length F _1
2 / F ₁ is preferably 10 or less. Further, in the configuration of the present invention in which the distance between the light source optical system and the liquid crystal display element is long, the numerical aperture (lens diameter / focal length) of the condenser lens
Has a small value of 0.5 or less, preferably 0.3 or less, but in order to efficiently emit light into the effective surface of such a condenser lens, F ₂ / F ₁ of the elliptic mirror is 4 or less. The above is preferable.

Further, according to the present invention, the transmission-scattering type display element 15 is caused by the shortage of the light component having a small angle with the optical axis at the second focal position, which occurs when the elliptical mirror 12 is used.
The non-uniformity of the in-plane light intensity distribution of the convex pyramidal prism 1 having an apex angle α of 100 ° to 150 ° or the apex angle β of 210 ° to 260 ° depending on the shapes of the light source 11 and the elliptical mirror 12. Is improved and made uniform by using the concave pyramidal prism 2 of In terms of light utilization efficiency and brightness distribution on the projection screen, the apex angle α is more preferably 120 °.
˜140 °, and the apex angle β is 220 ° to 240 °.

Further, a light source optical system comprising an elliptic mirror 12, a light source 11 and a convex or concave pyramidal prism,
A condensing lens arranged for each liquid crystal display element corresponding to G and R color light is used. Therefore, the small elliptical mirror 1
2, a large amount of light from the light source 11 can be used, and the light source optical system is downsized, so that the volume of the projection display device can be reduced.

In the projection type color display device of the present invention,
There are three possible arrangements of the condenser lens and the display element shown in FIGS. 9 to 11. These figures schematically show the arrangement of each component. First diaphragm 17, color separation means 141, light collecting means (light collecting lens) 1
3, the display element 15, and the second diaphragm 18 are shown.

Further, in these figures, a dichroic mirror is specifically used as the color separation means 141, and is arranged in the optical path after the light source optical system (conical prism). Similarly, a dichroic mirror is used as the color synthesizing means 142, and the dichroic mirror may be arranged after the display element and in the optical path of each color light. Alternatively, the color synthesizing means 142 does not provide the color synthesizing means to project and color synthesize on the screen. You may. In order to miniaturize the projection type color display device, it is preferable that the color synthesizing means is configured as in the embodiment of FIG.

In FIG. 9, plano-convex lenses are arranged on both the light input and output sides of the display element so that the light incident on the display element is parallel light. In FIG. 10, a condenser lens is arranged on the light incident side of the liquid crystal display element, and in FIG. 11 on the light emitting side of the display element. In the case of FIGS. 10 and 11, non-parallel light is incident on the display element. Either arrangement is possible,
When the electro-optical characteristics of the display element have angle dependence, the configuration of FIG. 9 in which incident light is parallel light is preferable, but six condenser lenses are required in the entire system.

On the other hand, in the configuration of FIG. 10, the condenser lens can be regarded as a part of the light source optical system and can be considered separately from the projection optical system. Therefore, compared with the configuration of FIG. Pixel adjustment becomes easy and the number of condenser lenses does not increase as compared with the conventional optical system.

As described above, by providing the first and second diaphragms and adjusting the two diaphragms, it is possible to make the projected light quantity and the contrast ratio correspond to the surrounding environment, and it becomes easier to see.

At this time, the second diaphragm 18 is a conical prism or the second light collecting surface of the light source optical system defined by the first diaphragm 17 has the second condenser lens (132B, 1B).
32G, 132R), and the same shape as the conjugate image of the light exit surface shape is preferable in terms of light utilization efficiency and scattered light removal efficiency. Further, in order not to increase the diameter of the projection lens, it is preferable to arrange the second diaphragm 18 at the pupil position of the projection lens. Next, examples will be described.

[0073]

【Example】

(Embodiment 1) FIG. 1 shows a projection type color display device 10.
In this embodiment, the light source 11 is arranged in the vicinity of the first focal point of the elliptical mirror 12, and the light emitted from the light source 11 is reflected by the elliptic mirror 12 and is shaped like a convex cone provided near the second focal point position. The light enters from the plane side of the prism 1, is refracted on the plane, propagates in the prism, is further refracted on the conical surface, and is emitted from the prism, thereby changing the azimuth distribution of the light flux after refraction and transmission. Then, two types of dichroic mirrors 141a, 1
After being color-separated into three color lights of B, G, and R by 41b, they are incident on the first condenser lenses 131B, 131G, and 131R, respectively, and become substantially parallel light.

Transmission / scattering type liquid crystal display elements 15B, 15
The non-scattered light that has passed through G and 15R is the second condenser lens 1
32B, 132G, 132R collects the light on the projection lens 19 of the projection optical system 20 and is not illustrated by the projection optical system (a three-lens configuration is shown in the drawing, but a compound multi-group lens system may be used). Although projected on the screen, scattered light is removed by the second diaphragm 18 and is not projected on the screen.

The light source 11 used here is a discharge light emission type metal halide lamp, a xenon lamp, a filament light emission type halogen lamp or the like, and any of them is an electrode of the light source section, a tube glass, a heat insulating film, a filament or the like. Since there is a light-shielding portion, the emitted light in the vicinity of the parallel azimuth angle with the optical axis emitted from the light source is small, and the reflected light from the elliptical mirror 12 has a small amount of the emitted light component in the vicinity of the parallel azimuth angle with the optical axis.

FIG. 1 without using a cone (conical prism)
In the case of the comparative example of No. 6, the light whose angle formed by the optical axis at the second focus is about 10 ° or less is insufficient, and the transmission-scattering type display element 1
A shadow appeared near the center of 5. However, the conical prism 1
In the case of the present invention using, the azimuth angle of the light flux is changed by refraction at the prism interface, and the shortage of light having an angle with the optical axis of about 10 ° or less is compensated for. The strength non-uniformity was corrected and made uniform.

Each part constituting this embodiment will be described. In this embodiment, the active-matrix-driven transmissive-scattering liquid crystal display element 15 has a diagonal display area of 3 inches and a pixel aperture ratio of 40%.
The maximum transmittance of B, 15G, and 15R is 30%.

The light source optical system includes a light source 11 (a light emitting arc length of 4 mm and a metal halide lamp of 150 W), an elliptical mirror 12 (first focal length F ₁ = 14 mm, second focal length F).
₂ = 134 mm, total depth H = 45 mm), convex cone-shaped prism 1 (vertical angle 130 °, bottom cross-section diameter 40 mm, height 12 mm, but the height of the inclined surface of the cone-shaped prism is 9.33 mm). To use. As the condenser lenses, the first condenser lenses 131B, 131G, 131R (focal length 22
5 mm plano-convex lens) and a second condenser lens 132B,
132G and 132R (plano-convex lens with a focal length of 225 mm) are used. Further, a first iris diaphragm 17 having a variable aperture diameter is provided between the conical prism 1 and the condenser lens near the second focal position of the elliptic mirror.

The liquid crystal display element used was one in which nematic liquid crystal having positive dielectric anisotropy was dispersed and held in an acrylic resin and encapsulated in a capsule shape. This is one of what is called a liquid crystal-polymer (resin) composite, and is an electro-optical element having a high light scattering ability, a high light transmittance, and a high-speed response. When the external electric field is turned on, the nematic liquid crystal molecules are aligned in response to the electric field, and the ordinary light refractive index at that time is almost matched with the refractive index of the resin. A mode that matches the rates is also possible).

Color separation means 141 emitted from the light source optical system
The color lights LB, LG, and LR that have been color-separated by a and 142b respectively pass through the transmission / scattering type liquid crystal display elements 15B, 15G, and 15R (transmission / scattering occurs depending on the pixel electrode depending on the image), and color combining means 142a and 142b. Are color-synthesized and are generated as color light LC. Then, of this color light, only the light that has passed through the second diaphragm 18 is projected onto the projection optical system 2.
An image is formed as a liquid crystal display image on the screen through 0 (projection lens 19).

At this time, the second aperture diameter variable second aperture position is set at the pupil position of the projection lens, which is the position where the conjugate image of the aperture diameter of the first diaphragm 17 is formed by the second condenser lenses 132B, 132G and 132R. The iris diaphragm 18 is arranged.

As a result, according to the present invention, a small light source optical system is used to make the illuminance distribution of the projected image uniform and increase the luminous flux which is the integrated light quantity within the screen surface without deteriorating the contrast ratio. be able to.

In particular, the remarkable shortage of the light amount near the center of the screen, which occurs when the convex or concave pyramidal prism of the present invention is not used, is improved, the maximum illuminance is obtained at the center of the screen, and it is bright as a large-area display screen. The display is easy to see.

In the case of the conical prism, any material may be used as long as it is a translucent material and an optical plane can be obtained. Usually, glass such as BK7, flint glass, Pyrex (registered trademark of Corning Incorporated) is polished and used. It is preferable to reduce the interface reflection by forming an antireflection film on the light refraction surface or to form a heat ray reflection film to transmit visible light and reflect heat rays.

In the present embodiment, instead of the dichroic mirror having an incident angle of 45 ° which is usually used as a color separation / combination system, the incident angle becomes about 30 ° in order to improve the light utilization efficiency without reducing the color purity. Although the dichroic mirror is arranged as described above, the dichroic mirror may be arranged at an incident angle of 45 ° as in the conventional case. In the present invention, the directivity can be improved because the long-focus condenser lenses (131B, 131G, 131R) are used. Moreover, the volume of the projection display device could be suppressed.

(Embodiment 2) In the light source optical system of Embodiment 1, instead of a single elliptic mirror, a composite condenser mirror in which an elliptic mirror and a spherical mirror are combined is used. Its component is an elliptical mirror 12A.
(First focal length f ₁ = 22 mm, second focal length f ₂ = 1
05 mm, total depth H = 25 mm, spherical mirror 12B (curvature radius Q = 50 mm, aperture diameter (large) DQ1 = 99 mm,
Aperture diameter (small) DQ2 = 60 mm, convex cone-shaped prism 1 (vertical angle 130 °, bottom cross-section diameter 40 mm, height 12 m)
However, the height of the inclined surface of the conical prism is 9.33m.
m) is used. In consideration of space saving and light utilization efficiency, for example, a radius of curvature Q = 45 mm and an opening diameter (large) DQ1 = 88 mm are preferable.

Here, as shown in FIG. 4, the spherical mirror 1
The center of curvature of 2B is located near the first focus of the elliptical mirror 12A, that is, in the light emitting portion of the light source 11. Further, the spherical mirror and the elliptical mirror have the same axis of rotational symmetry, and the spherical mirror has an opening (large) on the first focal point side of the elliptic mirror and an opening (small) on the second focal point side of the elliptic mirror. To do. Further, as in the first embodiment, the first iris diaphragm 17 having a variable aperture diameter is provided between the conical prism 1 and the condenser lens in the vicinity of the second focal position of the elliptic mirror. Other configurations are the same as those in the first embodiment.

By using the light source optical system having such a complex condenser mirror, a projection type display device having higher light utilization efficiency, that is, a larger screen light flux can be realized as compared with the first embodiment.

In the projection type color display device of the present invention,
By using a transmissive / scattering type liquid crystal display element as a fixed pattern or a simple matrix display and using it as an illuminating device, bright full color illumination with high color purity is possible and the illumination color and brightness can be adjusted at high speed.

(Embodiment 3) Referring to FIGS. 6 to 8,
Example 3 will be described. Provided is a projection-type color display device having a light source optical system with further features.

In the light source optical system of the present invention described above, the light emitting portion of the light source 11 is actually an approximate cylindrical object having a finite size. In this case, the elliptic mirror 12 has a first focal length of F ₁ and a second focal length of F ₂ (F ₂ > F ₁ ).
And the lengths of the light emitting portions of the light source 11 in the directions parallel and perpendicular to the rotational symmetry axis of the elliptic mirror 12 are R and S, respectively, and the cones (convex cone prisms or concave cone prisms). The first light source optical system is configured such that the vertices of the respective distances ΔR and ΔS with respect to the second focal point in the direction parallel to the rotational symmetry axis of the elliptical mirror 12 and the direction perpendicular to the second focal point are expressed by the following equation (7).

[0092]

[Formula 7] ΔR ≦ 0.25 × R × (F ₂ / F ₁ ) ² and Δ
S ≦ 0.5 × S × (F ₂ / F ₁ )

Further, in the first light source optical system, the length R of the light emitting portion of the light source 11 and the effective area S _A of the cone on the light incident side are respectively set as shown in the equation (8). A second light source optical system was constructed. Actually 1 mm ≦ R ≦ 7 m
Many light source lamps in the m range can be used.

[0094]

[Formula 8] 0.2 mm ≦ R ≦ 10 mm 0.2 × (R × F ₂ / F ₁ ) ² ≦ S _A ≦ 0.8 × (F ₂
× F ₁ )

In the first or second light source optical system described above, the focal length of the condensing means 13 is L ₁ (mm), and the cone light is the diffused light effective area on the light emission side. The third light source optical system is characterized in that the relation of Expression 9 is satisfied, where S _B (mm ² ) is the effective area perpendicular to the optical axis of the body or the aperture area of the first diaphragm 17. I will provide a.

[0096]

Equation 9] ^{_{L 1 2/1000 ≦ S B}} ≦ L 1 2/40

In the light source optical system of the present invention, orthogonal coordinates with the rotational symmetry axis of the elliptical mirror being the X axis, and the orthogonal axis perpendicular to the X axis being the Y axis and the Z axis at the end point on the first focal point side of the elliptic mirror. Considering the system, it is assumed that the light emitting portion of the light source placed at the first focal point position of the elliptical mirror has a cylindrical shape with a length of the X axis of R, a diameter of S in the Y axis and Z direction.

At this time, due to the converging action of the elliptical mirror, the image of the light emitting body placed at the first focus is formed as an enlarged image of the cylindrical light emitting body in the vicinity of the second focus position. About the magnitudes R ′ and S ′, approximately two relational expressions of Expression 10 hold.

[0099]

[Equation 10] R ′ = R × (F ₂ / F ₁ ) ² S ′ = S × (F ₂ / F ₁ ).

This is schematically shown in FIG. This is a case where a concave cone-shaped prism is used as the cone, and shows the light source 11 (light emitting unit 11a) of the light source optical system, the concave cone-shaped prism 2, the virtual image formation of the light emitting unit, and the optical axis ax. Similarly, FIG. 7 shows an enlarged schematic view of the vicinity of the center of the light emitting portion 11a and the concave cone prism. L _cen is the center of the light emitting portion. ΔR and ΔS will be described later. The light emission center of the light emitting portion is substantially arranged at the first focal point of the elliptic mirror, and the apex of the conical surface of the cone (concave cone prism) is substantially arranged at the second focal point position.

Therefore, if the apex of the cone-shaped object arranged near the second focal point is within the range of the enlarged image of this cylindrical light-emitting body, the light-beam homogenizing and condensing functions are exhibited. More preferably, the apex of the pyramid is arranged in the range of the R direction and the S direction defined by the equation 11 from the second focus position of the elliptical mirror. It should be noted that the principle of this virtual imaging can be applied to cones of other forms (in the case of concave and convex shapes and reflectors). This state is schematically shown in FIG.

[0102]

[Expression 11] ΔR ≦ 0.25 × R ′ = 0.25 × R × (F
₂ / F ₁ ) ² ΔS ≦ 0.5 × S ′ = 0.5 × S × (F ₂ / F ₁ )

When an ellipsoidal mirror is used as a condensing mirror, the actual light emitting portion which is not a point light source is arranged with the long side direction in the rotational symmetry axis direction of the ellipsoidal mirror, and is approximated by a long cylindrical shape of R ≧ 2 × S, for example. It Therefore, the range of ΔS can be defined as the following Expression 12.

[0104]

[Formula 12] ΔS ≦ 0.25 × R ′ = 0.25 × R × (F ₂ / F ₁ )

Also, the effective area S _{A of the} cone on the light incident side is
Preferably includes a magnified image of the illuminant at the second focal position. On the other hand, since the maximum radius of the elliptical mirror in the YZ axis direction is (F ₂ × F ₁ ) ^1/2 , the upper limit of the diameter of the effective surface of the cone on the light incident side is half the maximum diameter of the elliptic mirror. (F ₂ × F
₁ ) About ^1/2 is preferable. Therefore, it is preferable to satisfy the following condition of Expression 13.

[0106]

## EQU13 ## 0.2 × (R × F ₂ / F ₁ ) ² ≤S _A ≤0.
8 x (F ₂ x F ₁ )

The divergence angle φ (η) of the light beam emitted from the light source optical system is the focal length L _{1 of the} condensing lens which is the condensing means and the effective aperture D ₂ of the light emitting surface of the cone. By
It is related as shown in Expression 14. At this time, there can be two effective aperture diameters D ₂ of the light emitting surface of the conical object, that is, the effective sectional area diameter of the conical object itself and the aperture diameter of the aperture stop 17. Specifically, the dispersion angle ζ shown in FIG. 15 corresponds to φ.

[0108]

Tan (φ) = D ₂ / L ₁

Assuming that the preferable range of the dispersion angle of the light beam obtained from the light source optical system of the present invention is 2 ° ≦ φ ≦ 10 °, the effective area S _B (mm ² ) of the light emitting surface of the cone is expressed by the formula 15 It corresponds to satisfying the relationship of the expression A of Dispersion angle φ is 2 ° ≦ φ
The case of ≦ 6 ° corresponds to satisfying the relation of the expression B of Expression 15. Further, when the dispersion angle φ is 4 ° ≦ φ ≦ 8 °, it corresponds to satisfying the relation of the expression C of the expression 15.

[0110]

Equation 15] ^{_{L 1 2/1000 ≦ S B}} ≦ L 1 2/40 ..................... (A) L 1 2/1000 ≦ S B ≦ L 1 2/115 .................. (B ^{_{) L 1 2/260 ≦ S}} B ≦ L 1 2/64 ........................ (C)

In any of the light source devices using a transmissive cone in each of the above light source optical systems, the length R of the light emitting portion, the first focal length F ₁ , and the second focal length F ₂ When,
The diagonal dimension D _S (mm) of the display element 15 and the light collecting means 1
Provided is a light source optical system 101C, characterized in that the following relational expression 16 is satisfied between the focal length L ₁ (mm) of 3 and the refractive index n _P of the transmissive conical prism. .

[0112]

[Equation 16] 1 mm ≤ R ≤ 7 mm …………………… (a ₁ ) 1.5 R ≤ F ₁ ………………………… (a ₂ ) (F ₂ / F ₁ ) is given by either of the following, 5 ≦ F ₂ / F ₁ ≦ 12 ……………………………… when the condensing mirror of the light source optical system is composed of an elliptic mirror alone. (A ₃ −
1) When the condensing mirror of the light source optical system is composed of a compound condensing mirror of an elliptical mirror and a spherical mirror, 3 ≦ F ₂ / F ₁ ≦ 8 ………………………… (a ₃ −
_{2) 0.2 ≦ D S / L} 1 ≦ 0.5 .................. (a 4) 40 ≦ L 1 2 / S B ≦ 1000 .................. (a 5) 1.45 ≦ n _P ≤ 1.65 (a ₆ ) and, in the case of a convex cone prism, 100 ° ≤ α ≤ 150 ° (a ₇ ) or a concave cone prism , 210 ° ≦ β ≦ 260 ° ………………… (a ₈ )

Then, a projection type color display device using these light source optical systems is provided. In this case, the optical system such as the color separation / synthesis optical system around the display element is configured in the same manner as in the first and second embodiments.

The basic arrangement is similar to that of the first embodiment.
It is composed of a light source optical system, a RGB color separation means (dichroic mirror), and a projection optical system. The first characteristic is that the light source optical system of the present invention can obtain a high-directivity almost parallel light beam and a large light beam. Then, a high-performance projection type color display device is obtained by effectively using the light from the light source and combining it with an optical system capable of removing unnecessary light.

The light source optical system includes an elliptical mirror 12 and a light source 1.
1 and a light-transmissive convex-conical prism 1 or concave-conical prism 2, a convex-conical reflector 10 or a concave-conical reflector 20, and a condenser lens 13 as a condensing means. With this light source optical system, for example, the converging angle is 2 ° to
10 ° is obtained. Preferably, it is approximately 2 ° to 6 ° when R = 2 to 3 mm and approximately 4 ° when R = 5 mm.
It is possible to obtain a light beam with high directivity in the range of ° to 6 °. The closer the light emitting portion of the light source is to the more ideal point light source, the higher the degree of parallelism obtained.

In the present invention, a practical collimated light beam is generated by using a pyramid for a non-uniform light beam which is emitted from a light emitting section having a finite light emission length and is not uniform in space. First, there is the first feature.

In this case, the ratio D _S / R between the diagonal dimension D _S (mm) of the light irradiation surface on the display element or the display surface of the display element and the length R (mm) of the light emitting portion is taken as an index. There is a preferable range in which the degree of parallel light represented by the above-mentioned light collection angle and the light use efficiency are in harmony. Range of collection angle is 2 ° -10 °
In the case of, it is preferably in the range of 10 ≦ D _S / R ≦ 200, and in the case of 2 ° to 6 °, 20 ≦ D _S /
It is preferably in the range of R ≦ 200.

[0118]

In the projection type display device of the present invention, the light emitted from the light source is condensed by using the elliptical mirror 12 in combination with the conical object, so that the light collection efficiency is high and bright projection display is possible. It is possible. Further, by combining an elliptic mirror and a spherical mirror to form a compound condensing mirror, the condensing efficiency is further improved.

At the second focal position, a convex-cone prism or a concave-cone prism having a specific shape, and the first prism
The iris 17 is provided to remove the divergent light, so that the light source has a finite length, so that the light reflected by the elliptical mirror 12 and not going through the second focus position toward the transmissive scattering display element can be removed. The contrast ratio of the projected image can be improved.

Further, in this convex cone-shaped prism 1, the apex angle α
Is 100 ° to 150 °, and the apex angle β of the concave cone prism 2 is 210 ° to 260 °. Therefore, at the second focal position of the elliptic mirror that occurs when a light source having a light shielding portion and an elliptic mirror are used. The non-uniformity of the in-plane light intensity distribution of the transmission / scattering type display element 15 due to the lack of the light component parallel to the optical axis is improved, and the illuminance uniformity of the central portion is particularly excellent while taking a large amount of light of the projected image. Moreover, a bright and high-contrast projection display device can be obtained.

Further, by disposing the condensing lenses having a long focal length in the optical paths of the respective color lights in accordance with each liquid crystal display element corresponding to each color, the volume of the projection type display device is not increased. It is possible to generate incident light on the liquid crystal display element having high brightness and high directivity.

In addition to the above, the present invention can be applied in various ways within a range that does not impair the effects of the present invention.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a projection type display device of the present invention.

FIG. 2 is an enlarged view of a light source optical system using a convex cone prism of the present invention.

FIG. 3 is an enlarged view of a light source optical system using the concave cone prism of the present invention.

FIG. 4 is an enlarged view of a light source optical system using an elliptical mirror, a spherical mirror, and a convex cone prism.

FIG. 5 is an optical path diagram in the vicinity of a convex cone prism.

FIG. 6 is a block diagram of a third embodiment of the present invention.

FIG. 7 is a partially enlarged view showing the relationship of virtual imaging of the light source optical system of the present invention.

FIG. 8 is an enlarged view showing a virtual image formation in the vicinity of a cone according to the present invention.

FIG. 9 is a block diagram showing a first arrangement relationship (two-lens condenser lens configuration) of the color separation means, the display element, and the condenser lens of the present invention.

FIG. 10 is a block diagram showing a second arrangement relationship (front condenser lens) of the color separation means, the display element, and the condenser lens of the present invention.

FIG. 11 is a block diagram showing a third arrangement relationship (post-condensing lens) of the color separation means, the display element, and the condensing lens of the present invention.

FIG. 12 is an optical path diagram in the vicinity of a prism body.

FIG. 13 is a block diagram of a light source optical system of the present invention.

FIG. 14 is a graph showing characteristics of a light collection angle and a contrast ratio when a liquid crystal display device including a liquid crystal resin composite is used.

FIG. 15 is an optical path diagram from the light source optical system of the present invention to a second diaphragm.

FIG. 16 is a block diagram showing a comparative example.

[Explanation of symbols]

1: Convex Cone Prism 2: Concave Cone Prism 10: Projection Color Liquid Crystal Display Device 11: Light Source 11a: Light Emitting Unit 12, 12A: Elliptical Mirror 12B: Spherical Mirror 131R, 131G, 131B: Condensing Lens 132R, 132G , 132B: Condensing lens (field lens) 15R, 15G, 15B: Display element 17: First diaphragm 18: Second diaphragm 20: Projection optical system 141, 141a, 141b: Color separation means 142, 142a, 142b: Color synthesis means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nariyuki Serizawa 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Within Asahi Glass Co., Ltd. Central Research Institute Co., Ltd.

Claims (11)

[Claims] 1. A light source optical system that emits light from a light source, a color separation unit that color-separates the light from the light source, a condensing unit that condenses the colored light, and a light scattering ability that changes according to an external signal. A projection type color display device comprising a transmission / scattering type display element provided for each of the display elements and a projection optical system for color-synthesizing the color lights passing through the display element and projecting the color display light on a screen or the like. The light source optical system includes a light source, an elliptic mirror, and a conical prism, and the light condensing unit is in the optical path after the color separating unit and is provided on at least one of the light incident side or the light emitting side of each display element. A projection type color display device, characterized in that the color light provided in the optical path from the color separation means to the light condensing means is non-parallel light. 2. The projection type color display device according to claim 1, wherein the light source optical system is provided with a light source, an elliptic mirror, a spherical mirror and a conical prism, and the light source is located near the first focal point of the elliptic mirror.
A cone-shaped reflector is arranged near the position of the second focal point of the elliptic mirror, and a spherical mirror having a curvature center near the position of the first focal point of the elliptic mirror is arranged, and the depth H of the elliptic mirror and the first focal length f ₁ are set. , K = H / f ₁ is 1 to 1.3, and the reflecting surface of the spherical mirror covers the first focal point of the elliptical mirror from the second focal direction side and has an opening on the second focal direction side. Characteristic projection type color display device. 3. The projection type color display device according to claim 1 or 2, wherein the first condensing means is disposed on the light incident side of the display element and the second condenser is disposed on the light emitting side of the display element. A projection type color display device comprising: a light unit. 4. The projection type color display device according to claim 1, wherein the light condensing means is arranged on the light incident side of the display element. 5. The projection type color display device according to claim 1, wherein a first diaphragm is provided at a position between the cone-shaped prism and the color separation means. Projection type color display device. 6. The projection type color display device according to claim 1, wherein the image of the cone-shaped prism or the first diaphragm is substantially the same as the image at the position where the image is formed by the light collecting means. A projection type color display device characterized in that a second diaphragm having a shaped opening is arranged. 7. The projection type color display device according to claim 1, wherein a liquid crystal display element is used as a display element, and a nematic liquid crystal having a positive dielectric anisotropy is provided between the substrates with electrodes. Has a liquid crystal solidified substance complex dispersed and held in a solidified substance matrix, and the refractive index of the solidified substance matrix is used to be either the ordinary light refractive index (n ₀ ) or the extraordinary light refractive index (n _E ) A projection type color display device characterized by being a liquid crystal display element matched with one side. 8. A light source optical system for emitting a light source light, a color separation means for color-separating the light source light into color light, a light condensing means for condensing the color light, and a light scattering ability which changes according to an external signal. It is composed of a transmission / scattering type display element provided for each color, a color separation means for color-synthesizing each color light that has passed through the display element, and a projection optical system for projecting the color-synthesized color display light onto a screen or the like. A projection type color display device, wherein a light source optical system is provided with a light source, an elliptic mirror or a composite collecting mirror, and a conical prism, and the condensing means is in the optical path after the color separating means, A projection-type color display device, characterized in that color light is provided on each of the light incident side and the light emitting side, and the color light in the optical path from the color separating means to the light-incident-side condensing means is non-parallel light. 9. The projection type color display device according to claim 1, wherein the convex cone prism has an apex angle α of 100 ° to 150 °, or the concave cone prism has an apex angle β. Is 210 ° to 260
A projection type color display device characterized by being set to °. 10. The projection type color display device according to claim 1, wherein the light condensing means includes a first light condensing means arranged on a light incident side of the display element and a light of the display element. A projection type color display device comprising: a second condensing unit arranged on the exit side and condensing transmitted light from a display element at a pupil position of a projection lens in a projection optical system. 11. An illuminating device comprising the projection type color display device according to claim 1.