JPH08234197A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE: To obtain a compact projection type liquid crystal display device excellent in image quality performance such as brightness by providing an ellipsoidal mirror and a spherical mirror and setting a liquid crystal display element in the vicinity of the position of a focal point far from a light source possessed by the ellipsoid of the ellipsoidal mirror. CONSTITUTION: Light B1 emitted from the 1st focal point P toward the ellipsoidal mirror 5 reaches the 2nd focal point P' on an optical axis 18 of the light reflected by the mirror 5, and the light emitted from the point P and directly reflected by the mirror 5 all reaches the point P'. Meanwhile, in the case the center of a spherical surface being the reflection surface of the spherical mirror 6 is matched with the point P, the light B2 emitted from the position of the point P toward the mirror 6 is reflected by the mirror 6, returns to the point P again, goes toward the mirror 5, and is reflected by the mirror 5, then reaches the point P'. By such actions, the light made incident on the mirrors 5 and 6 out of the light emitted from the point P all reaches the point P'. Therefore, by arranging the liquid crystal element in the vinicity of the point P', light utilization efficiency is improved, and the bright and compact display device excellent in the image quality performance is obtained.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as an image display apparatus, an illumination means irradiates an optical image formed on a light valve in accordance with a video signal as a change in optical characteristics, and the optical image is screened by the projection means. There is a projection-type display device that magnifies and projects on top. Many proposals have been made for a projection type liquid crystal display device using a liquid crystal display element as a light valve of such a display device. The structure of a twisted nematic (TN) type liquid crystal display element, which is a typical example of a liquid crystal display element, has a polarization direction before and after a liquid crystal cell formed by injecting liquid crystal between a pair of transparent substrates having transparent electrode coatings. Are two polarizers arranged so that they are different from each other by 90 °, and by combining the action of rotating the polarization plane by the electro-optical effect of liquid crystal and the action of selecting the polarization component of the polarizer, Image information is displayed by controlling the amount of transmitted light. In recent years, the transmissive or reflective liquid crystal display element itself has been downsized, and performances such as resolution have been rapidly improved, and a display device using the liquid crystal display element has been downsized and improved in performance. As a result, a projection type liquid crystal display device has been newly proposed as an image output device of a personal computer as well as a conventional image display by a video signal.

[0003]

However, the conventional projection type liquid crystal display device has problems that it is large and that the performance of the finally obtained image such as brightness is insufficient. The miniaturization of the light valve, that is, the liquid crystal display element itself is effective for the miniaturization of the entire display device. However, when the liquid crystal display element is miniaturized, the area illuminated by the illuminating means becomes smaller, so that the total amount of light flux emitted from the light source is There is a problem such that the ratio of the amount of luminous flux irradiated on the liquid crystal display element (hereinafter, referred to as light utilization efficiency) becomes low. As a result, it has been difficult to reduce the size of the entire device and improve performance such as brightness at the same time. Further, in the case of the projection type liquid crystal display device, various elements such as the optical characteristics of the projection lens and the optical characteristics of the liquid crystal display element affect the image quality performance in addition to the above illumination means. However, it is difficult to obtain a small-sized display device with good image quality performance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve such conventional problems and to provide a projection type liquid crystal display device which is small in size and has good image quality performance such as brightness.

[0005]

In order to solve the above-mentioned problems, the present invention has an illumination means having a light source and having a function of irradiating the surface to be irradiated with light emitted from the light source, and a liquid crystal for modulating the light. In a projection type liquid crystal display device having a display element and a projection means for projecting light emitted from the liquid crystal display element, the illuminating means has at least one ellipsoidal mirror and one spherical mirror, and the liquid crystal display The element is installed in the vicinity of the focus position farther than the light source that the elliptical surface of the ellipsoidal mirror has, and a convex lens is provided between the light source and the liquid crystal display element and between the liquid crystal display element and the projection means. The configuration is provided.

[0006]

Next, the operation of the present invention will be described.

FIG. 1 is a block diagram of an optical system of a projection type liquid crystal display device according to the present invention.

In FIG. 1, a light source 1 is a white lamp such as a metal halide lamp, a xenon lamp and a halogen lamp. In the illumination means 2 composed of the light source 1, the elliptical mirror 5 and the spherical mirror 6, the light emitted from the light source 1 is reflected by the elliptic mirror 5 and the spherical mirror 6 and enters the condenser lens 7. The condenser lens 7 has a positive refracting power and has a function of further condensing the light emitted from the illumination means 2, and the light passing through the condenser lens 7 irradiates the liquid crystal display element 3. The light that has passed through the liquid crystal display element 3 is projected by a projection means 4 such as a zoom lens.
The light enters the field lens 8 having the function of causing the light to enter the screen, and then passes through the projection means 4 and reaches the screen 9. The image formed on the liquid crystal display element 3 by the field lens 8 and the projection means 4 is enlarged and projected on the screen 9 to function as a display device.

Next, the operation of the main part of the projection type liquid crystal display device according to the present invention will be described in detail. FIG. 2 is a principle sectional view showing the operation of the illumination means of the projection type liquid crystal display device of the present invention.

FIG. 2 shows how the light emitted from the light source is reflected by the ellipsoidal mirror 5 and the spherical mirror 6. The points P and P ′ shown in the figure represent the positions of the first focus and the second focus of the ellipsoidal surface which is the reflection surface of the ellipsoidal mirror 5, respectively. The light B1 emitted from the point P toward the ellipsoidal mirror 5 is reflected by the ellipsoidal mirror 5 and reaches the point P ′ on the optical axis 18. Therefore, all the light emitted from the point P and directly reflected by the ellipsoidal mirror 5 reaches the point P ′. On the other hand, when the center of the spherical surface which is the reflecting surface of the spherical mirror 6 is made to coincide with the point P, the light B2 emitted from the position of the point P toward the spherical mirror 6 is reflected by the spherical mirror 6 and returns to the point P again to form an ellipse. It goes to the plane mirror 5 and reaches a rear point P ′ reflected by the ellipsoidal plane mirror 5. Due to these actions, among the light emitted from the position of the point P, all the light incident on the ellipsoidal mirror 5 or the spherical mirror 6 reaches the point P ′ in principle. The light B2 has not hitherto hit the surface to be illuminated, such as a liquid crystal display element, and improves the light utilization rate by disposing the liquid crystal display element near the point P ′ in the configuration shown in FIG. be able to. Further, like the conventional illumination means, if an attempt is made to improve the light utilization efficiency with only one reflecting mirror such as the ellipsoidal mirror 5, the reflecting mirror becomes large,
Along with this, a projection lens having a small F-number is required as a projection means, which causes a problem that the projection lens becomes large.

FIG. 3 is a configuration diagram showing an example of a light source in the projection type liquid crystal display device of the present invention.

FIG. 3 shows a lamp 10 as an example of the light source 1.
Is represented. In the figure, 13 is an arc tube made of quartz glass or the like, and is filled with a gas such as mercury or argon for operating as a lighting device for a metal vapor discharge lamp.
Further, FIG. 11 shows an electrode, 12 a heat insulating film, and 15 an arc tube 1.
Molybdenum foil having the function of maintaining the airtightness of 3,
14 is a lead wire, 16 is a base, and the pair of electrodes 1
Light is emitted from the light emitting unit 17 due to the discharge between the two. Here, the heat insulating film 12 is made of zirconia or the like,
It has the effect of maintaining the temperature of the arc tube and increasing the vapor pressure, and thereby has the effect of obtaining sufficient continuous light emission performance or lamp life. However, of the light radiated from the light emitting portion 17, the light incident on the heat insulating film 12 is absorbed or diffused and reflected, so that the light is not emitted by the illuminating means using the conventional lamp in which the heat insulating film is applied over a wide range. The usage efficiency was low. In the configuration shown in FIG. 3 of the present invention, the lamp 1
When 0 is used, the heat insulating film 12 is provided in a range matching the shape of the spherical mirror 6. That is, the shape of the heat retaining film is determined so that the light B emitted from the light emitting unit 17 shown in FIG. 3 enters the spherical mirror 6 shown in FIG. 2 without being absorbed or reflected by the heat retaining film 12. As a result, in the illumination means that combines the lamp 10 and the configuration shown in FIG.
Conventionally, the light that has been absorbed or diffusely reflected by the heat retaining film 12 can be effectively used for irradiation, resulting in high light utilization efficiency. On the other hand, when the lamp is provided so that the light emitting unit 17 is located near the point P in FIG. 2, the light emitted from the light emitting unit 17 and incident on the spherical mirror 6 is reflected and again directed toward the light emitting unit as described above. Return. Therefore, the light reflected by the spherical mirror 6 hits the arc tube 13 of the lamp, and there is an effect that the temperature of the arc tube is maintained and the vapor pressure is increased. That is, the spherical mirror 6 has an action equivalent to that of the conventional heat retaining film. Therefore, by combining the reflector configuration shown in FIG. 2 with the lamp shown in FIG. 3, the interaction between the two does not deteriorate the light emitting performance and life of the lamp even if the application range of the heat insulating film is reduced. It is possible to obtain a lighting means with high utilization efficiency.

In the structure of the present invention, the heat insulating film 12 may be omitted if the efficiency of returning the light from the spherical mirror 6 to the lamp is high and sufficient light emitting performance and life can be obtained. Further, in order to allow the spherical mirror 6 to have a sufficient function of the conventional heat insulating film 12, the reflecting surface of the spherical mirror 6 is formed by aluminum vapor deposition or the like rather than a dichroic mirror that reflects only a visible light region. It is better to do.

Next, the function of irradiation by the lamp and the reflecting mirror in the present invention will be described. FIG. 4 shows the lamp 1
It is an example of a luminance distribution characteristic of 0.

The horizontal axis of the figure shows the position along the electrode of the light emitting portion 17, and the central portion of the horizontal axis corresponds to the center of the light emitting portion 17. The vertical axis represents the relative luminance when the light emitting unit 17 is viewed from the direction shown in FIG. Due to the action of the reflecting mirror shown in FIG. 2, when the point P has a point light source, the light emitted from the point P is reflected by the ellipsoidal mirror 5 and the spherical mirror 6 to the point P ′.
To reach. However, in general, a lamp used as a light source has a certain size of the light emitting portion 17 as shown in FIG. 3, and therefore has a luminance distribution as shown in FIG. For example, in a metal halide lamp that emits light by electric discharge between electrodes, as shown in FIG. 4, the light emission luminance is high in a portion close to the electrodes and slightly low in a central portion between the electrodes. In the present invention, the liquid crystal display element 3 which is a surface to be illuminated is provided in the vicinity of the point P ′ shown in FIG. Is set to be approximately the size of the liquid crystal display element 3. As a result, a distribution of light energy close to the brightness distribution of the light emitting section 17 is projected on a certain cross section along the optical axis of the liquid crystal display element 3. Usually, when irradiating a particularly small liquid crystal display element, with an illuminating means using only a combination of a lamp and a reflecting mirror, the brightness distribution of the illuminated surface is non-uniform with only the center bright and the periphery dark. However, by setting the elliptical shape considering the brightness distribution of the lamp as described above,
It is possible to realize an easy-to-see image in which the center is bright on the entire surface of the liquid crystal display element 3 and the ratio of peripheral illuminance to the center is high.

FIG. 5 is a principle sectional view showing the relationship between the illuminating means, the condenser lens and the liquid crystal display element in the present invention.

In the configuration shown in the figure, the size D of the opening of the spherical mirror 6 is set by the aperture of the ellipsoidal mirror 5 and the reflecting surface of the spherical mirror and the size of the liquid crystal display element 3. That is, of the light emitted from the light emitting unit 17, the light reflected at the outermost periphery of the ellipsoidal mirror 5 and reaching the outermost periphery of the liquid crystal display element 3 is
The size D of the opening of the spherical mirror 6 is set so as not to block the spherical mirror 6. Further, if the outer diameter of the spherical mirror 6 is large, the entire display device becomes large, and if it is too small, the area of the reflecting surface of the spherical mirror 6 becomes small due to the above-mentioned restriction of the size D of the opening. As a result, the light utilization efficiency is lowered, and therefore the optimum size is set in consideration of these.

On the other hand, the condenser lens 7 shown in FIG. 5 mainly has two functions. First, as shown in the figure, the condenser lens 7 having a positive refractive power is a spherical mirror 6
The light has a function of further condensing the light emitted from the opening part and incident on the condenser lens 7, whereby the light is collected in the liquid crystal display element 3 and the light utilization efficiency is high. further,
The condenser lens 7 displays the light diffused in the vicinity of the liquid crystal display element 3 without following the principle light path described above due to the manufacturing tolerance of the elliptical mirror 5 or the spherical mirror 6 and further the lamp. It has a function of condensing light on the element 3. The condensing function of the condenser lens and the function of the field lens 8 shown in FIG. 1 have the effect of guiding most of the light that has passed through the liquid crystal display element to the projection means, and as a result, a bright projected image can be realized. If there is no condenser lens, the refractive power of the field lens 8 shown in FIG. 1 increases, the resolution performance deteriorates, and the number of lenses increases. Another condenser lens
One effect is that the liquid crystal display element 3 is formed by the condenser lens 7.
This is an action to make the center of gravity of the energy of light passing through a certain point on the direction substantially parallel to the optical axis. As a result, the optical characteristics such as the contrast of the liquid crystal display element 3 are made uniform over the entire screen, and finally a display device having good image quality performance can be obtained. With the above-described operation, a liquid crystal display device that is bright and has good image quality performance can be realized even if the size of the entire display device is reduced by using a small liquid crystal display element.

[0019]

EXAMPLES Next, specific examples of the present invention will be described.

FIG. 6 is a block diagram showing an embodiment of the projection type liquid crystal display device according to the present invention.

In the embodiment shown in FIG. 6, a transmissive liquid crystal display element is used as a liquid crystal light valve corresponding to three so-called three primary colors of R (red), G (green) and B (blue), respectively. 3 shows a three-plate projection type display device using a total of three sheets. In this embodiment, light emitted from a lamp 10 such as a metal halide lamp, which is a light source, is reflected by an ellipsoidal mirror 5 or a spherical mirror 6, and then a thin glass plate is formed at a Brewster angle with respect to the optical axis. It is incident on the prepolarizer 22 which has a function of passing almost only P-polarized light out of indefinitely polarized light, which is formed by stacking several sheets. The light that has passed through the prepolarizer 22 passes through a heat ray cut filter 23 that reflects heat rays such as infrared rays and ultraviolet rays and passes visible rays, and then is arranged at an angle of 45 ° with respect to the optical axis. The R (red) transmission dichroic mirror-24 reflects G (green) and B (blue) light, and transmits R (red) light. The reflected R ray is a total reflection mirror.
The optical path is bent by 29, passes through the condenser lens 7 and the incident side polarization plate 20, enters the liquid crystal display element 3R composed of a counter electrode, liquid crystal, etc., and is provided on the light emission side of the liquid crystal display element 3R. It passes through the exit side polarization plate 21 and the field lens 8. The R ray emitted from the field lens 8 passes through the dichroic mirror 26 having the function of passing the R ray, and after being reflected by the dichroic mirror 27 having the action of reflecting the R ray and the B ray, for example, Incident on a projection means 4 such as a mullens. On the other hand, the G ray and the B ray reflected by the R transmission dichroic mirror-24 are incident on the B reflection dichroic mirror-25, and the B ray is reflected by the mirror and passes through the condenser lens 7 and the incident side polarization plate 20. Then, the light enters the liquid crystal display element 3B and passes through the emission side polarization plate 21 and the field lens 8 provided on the light emission side of the liquid crystal display element 3B. The B ray emitted from the field lens 8 is reflected by the dichroic mirror 26 having a function of reflecting the B ray, and is incident on the projection means 4 after being reflected by the dichroic mirror 27 together with the R ray. Also,
The G ray that has passed through the dichroic mirror 25 passes through the condenser lens 7 and the incident side polarization plate 20, is incident on the liquid crystal display element 3G, and is the emission side polarization plate 21 provided on the light emission side of the liquid crystal display element 3G. And through the field lens 8. The G ray emitted from the field lens 8 is reflected by the total reflection mirror 28, and is reflected by the dichroic mirror.
After passing through 27, it is incident on the projection means 4 together with the R and B rays. By the above, the light rays corresponding to R, G, and B are separated and combined by the color separation means and the color combination means,
The projection means 4 enlarges the image on the liquid crystal display element corresponding to each of R, G and B, and synthesizes the image of each color on the screen to obtain the enlarged real image. In the figure, 32 is a power supply circuit, 43 is a video signal circuit, and 33 is a blowing duct which has a function of guiding the wind from the case 19 of the lighting means to the blowing fan 34.

The illuminating means and the projecting means are arranged such that their optical axes are parallel to each other, and further, the color separating / combining means is composed of the color separating means, the liquid crystal display element and the color combining means. By arranging the power supply circuit 32 and the video signal circuit 42 through the unit 44 as shown in the figure, the entire device is miniaturized and the device shape is rectangular, and the shorter side of the rectangle is closer to the screen side. The shape can be adapted to the form of use in a conference room or the like used for.

The lamp 10 in this embodiment is, for example, a metal halide lamp as shown in FIG. The operation of the illumination means including the lamp is as described above, and will not be repeated here.

Further, as the liquid crystal display element 3 in this embodiment, for example, the diagonal length of the screen is 1 inch class p-SiTF.
The T-type transmissive liquid crystal panel is used to realize miniaturization of the entire device. In the liquid crystal display element 3, an incident side polarization plate 20 which is a polarizer for transmitting linearly polarized light to the light incident side and the light exit side of the display element and a rotation of 90 ° with respect to the incident side polarization plate 20. The exit-side polarization plate 21 that is a polarizer that transmits linearly polarized light having the above-mentioned polarization plane is provided, and the action of rotating the polarization plane by the electro-optical effect of the liquid crystal in the liquid crystal display element 3 and the incidence-side polarization that is the polarizer. Board 2
By combining 0 and the polarization component selection function of the exit side polarization plate 21, the amount of transmitted incident light is controlled to display image information.

Reference numeral 19 in FIG. 6 shows a case of the illumination means. If the image quality performance such as sufficient brightness as a display device cannot be obtained due to the life of the lamp, the case 1
It is possible to exchange every 9 units. FIG. 7 is a sectional configuration diagram showing an embodiment of the illumination means of the projection type liquid crystal display device according to the present invention.

In the example shown in the figure, the ellipsoidal mirror 5 and the spherical mirror 6 are arranged via a holding plate 36 of the reflecting mirror, whereby the positions of the ellipsoidal mirror 5 and the spherical mirror 6 are accurately adjusted. I am trying to install it well. In particular, when a small liquid crystal display element is used, or when the light utilization efficiency is high, the position accuracy of the ellipsoidal mirror 5 and the spherical mirror 6 and the like becomes strict, so it is preferable to arrange them through one member. It is valid. Further, in the example shown in FIG. 7, the pressing plate 36 is sandwiched by the other members 35 and 37, so that the mounting work at the time of manufacturing can be easily performed.

FIG. 8 shows an example of a structure in which a reflecting mirror such as an ellipsoidal mirror is attached to the holding plate 36.

FIG. 8 is a view of the holding plate 36 in FIG. 7 viewed from the left side in FIG. 7 along the optical axis direction. In the example shown in the figure, a leaf spring 38 is fixed to the holding plate 36,
The elliptical mirror 5 is held by the elasticity of the leaf spring. Further, the holding plate 36 is provided with a vent 39, which secures a flow path for the air from the fan, cools the elliptical mirror 5, the spherical mirror 6 and the lamp 10 to maintain an appropriate temperature. There is.

FIG. 9 shows an example of a holding structure for the condenser lens and the incident side polarization plate.

The example shown in FIG. 3A is the incident side polarization plate 2
0 is attached to the glass plate 41, and the glass plate and the condenser lens 7 are fixed to the folder 40 together, whereby the number of parts is reduced. Further, in order to further reduce the number of parts, as shown in FIG. 7B, the condenser lens 7 may be a plano-convex lens, and the incident side polarization plate 20 may be directly attached to the plane side of the condenser lens 7.

FIG. 10 shows an embodiment of the condenser lens.

Since the image display portion of the liquid crystal display element usually has a rectangular shape, if the condenser lens 7 is a circular lens, there will be a portion that does not contribute to the irradiation of the liquid crystal display element. Therefore, as shown in FIG. 10, it is possible to reduce the size by cutting the condenser lens into a rectangle according to the shape. FIG. 11 shows an example of holding the condenser lens 7.

The figure shows an example in which the condenser lens 7 is fitted in the folder 40. As a result, the condenser lens shown in FIG. 9 can be fixed,
As a result, it is possible to obtain a device having good holding accuracy.
Although the condenser lens 7 has a rectangular shape,
The peripheral portion may be shaped like a barrel according to the shape of the light flux that contributes to the liquid crystal display element.

FIG. 12 shows another embodiment from the liquid crystal display element to the projection means of the projection type liquid crystal display device according to the present invention.

In the example shown in the figure, the optical axis 18 of the liquid crystal display element 3 and the optical axis 42 of the field lens 8 and the projection means 4 are decentered in parallel by δ. This allows
The image on the screen 9 finally obtained on the display device,
The center of the image can be decentered from the optical axis 42 on the projection means side without distortion. This makes it possible to project the image at a position where it is easy to see. Incidentally, in the example shown in the figure, the field lens 8 is cut under the condition that the light emitted from the liquid crystal display element 3 is not shielded to realize the miniaturization.

In the above embodiment, the projection means 4 such as the field lens 8 and the zoom lens are properly shaped so as to satisfy the optical performance such as the F value, the focal length and the resolution. Needless to say

Next, specific numerical examples in the above embodiment will be described with reference to the explanatory views of FIGS. 13 and 14.

In the structure shown in FIG. 13, a metal halide lamp 10 having an interelectrode distance l of 3 mm shown in FIG. 13 is used, and the shape of the reflecting surface of the ellipsoidal mirror 5 is set to a first focal length f1 of 15.
mm, the second focal length f2 is an elliptical surface having a diameter of 250 mm, and the reflecting surface of the spherical mirror 6 has a spherical shape with a radius of curvature of 50 mm. The lamp 10 is installed such that the center between the electrodes is located at the first focal length position of the ellipsoidal mirror 5, and the optical distance of the liquid crystal display element 3 is at the second focal length position of the ellipsoidal mirror 5. So that the distance t is 5 mm on the lamp side of the liquid crystal display element 3.
A 00 mm condenser lens 7 is provided. A projection type liquid crystal display device having a structure shown in FIG. 6 using the structure of the present illumination means, a field lens having an F value of 3 in total, and a projection means, the liquid crystal display having a diagonal length of 1.3 inches. A projection type liquid crystal display device having a high light utilization efficiency of about 50% and a bright screen image and good image quality performance was obtained by using the element. In this numerical example, for example, the shape of the ellipsoidal mirror 5 changes depending on the distance l between the electrodes of the lamp and the size of the liquid crystal display element. FIG. 14 shows the elliptical mirror 5
3 shows the amount of spread d'of light with respect to the first focal length f1.

The horizontal axis in FIG. 14 represents the first focal length f1 of the ellipsoidal mirror 5 shown in FIG. 13, and the vertical axis represents the light emitted from both ends of the lamp light emitting section 17 shown in FIG. The amount of spreading d'is shown above. Note that FIG. 14 shows the case where the second focal length of the ellipsoidal mirror is constant. 14
As can be seen in Fig. 3, the spread amount decreases as the first focal length of the ellipsoidal mirror increases. Further, the line shown by a in FIG. 14 shows that the inter-electrode distance l of the lamp is large and b is small, respectively. The smaller l is, the smaller the light spread amount is. It is effective to improve the light utilization efficiency that the spread amount d ′ of light is equal to or smaller than the size d of the surface substantially perpendicular to the optical axis of the liquid crystal display element, and as shown in FIG. The first focal length f1 of 1 corresponds to the distance 1 between the lamp electrodes and the size d of the liquid crystal display element and needs to be set appropriately. Specifically, the liquid crystal display element size d is in the range of 0.7 inch to 2 inches,
Also, under the condition that the inter-electrode distance 1 is in the range of 2 mm to 4 mm, the first focal length f1 of the ellipsoidal mirror is 10 m.
It is preferably between m and 20 mm. If the ellipsoidal mirror first focal length f1 is smaller than 10 mm, the light utilization efficiency is deteriorated, the distance between the lamp and the ellipsoidal mirror becomes too short, and a thermal problem occurs. Distance f
When 1 is larger than 20 mm, the uniformity of the screen is deteriorated, and the incident angle θ to the liquid crystal display element shown in FIG. further,
Under the conditions of the size d of the liquid crystal display element and the distance 1 between the lamp electrodes, it is desirable that the radius of curvature of the spherical mirror 6 be set in the range of 30 mm to 60 mm. Spherical mirror 6
If the radius of curvature of is less than 30 mm, the amount of light returned to the ellipsoidal mirror 5 decreases, and problems such as deterioration of light utilization efficiency occur,
Further, when the radius of curvature of the spherical mirror 6 is larger than 60 mm, there arises a problem that the entire display device becomes large. The above specific examples satisfy all of the above conditions, and thus a projection type liquid crystal display device with good performance can be obtained.

In the structure of the present invention, any one or more of the ellipsoidal mirror 5, the spherical mirror 6, the condenser lens 7 and the field lens 8 has a shape in which the peripheral shape is changed with respect to the paraxial axis. Therefore, it is effective for the uniformity of screen illuminance or the improvement of light utilization efficiency. For example, when the central portion of the optical axis of the condenser lens 7 has an aspherical shape close to a flat surface, the illuminance ratio of the periphery to the center is further increased, and the illuminance uniformity on the screen is improved.

Next, the flow channel structure of the projection type liquid crystal display device according to the present invention will be described with reference to FIGS.

FIG. 15 is a schematic block diagram of the embodiment shown in FIG. 6 viewed from the side. Further, FIG. 16 is a principle view showing a flow path of the wind of the color separation / synthesis unit 44.
In the present embodiment, the sucked outside air is made to flow from the six outlets, and the flow of the wind is shown by W _{1 to} W ₆ . The suction fan 46 draws in air from the outside and sucks it in, and the duct 45 blows out air from the outlet 47 and the power supply circuit 32 corresponding to the R, G, and B liquid crystal light valves 3.
Of the cooling air outlet 48, the air outlet 49 for cooling the video signal circuit 43, the air outlet 49 for cooling the video signal circuit 43, and the air outlet 50 for cooling the prepolarizer 22. It is like this. Further, the wind that has cooled the prepolarizer-22 is supplied with the ventilation holes 51.
It is also used for cooling the lighting means 2 after passing through. The air blown from each air outlet is blown out of the projection type liquid crystal display device by the air outlet duct 33 and the air outlet fan 34.

In this embodiment, the color separation / synthesis unit 44 is used.
The suction duct 45 and the suction duct 45 are separate parts, but they may be integrated.

By constructing the air flow path as described above, even if the entire liquid crystal display device is downsized, sufficient cooling can be performed with a small number of fans, especially in the vicinity of the liquid crystal display element which is vulnerable to heat. Can be realized.

[0045]

As described above, according to the present invention, it is possible to realize a small-sized projection type liquid crystal display device in which the light emitted from the light source is efficiently used, that is, the light is bright and the image quality is excellent.

[Brief description of drawings]

FIG. 1 is an optical system configuration diagram of a projection type liquid crystal display device of the present invention.

FIG. 2 is a principle sectional view showing a main part of a projection type liquid crystal display device of the present invention.

FIG. 3 is a configuration diagram showing an embodiment of a light source in the projection type liquid crystal display device of the present invention.

FIG. 4 is a characteristic diagram of a light source in the projection type liquid crystal display device of the present invention.

FIG. 5 is a principle sectional view showing a main part of a projection type liquid crystal display device of the present invention.

FIG. 6 is a configuration diagram showing an embodiment of a projection type liquid crystal display device of the present invention.

FIG. 7 is a configuration diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

FIG. 8 is a configuration diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

FIG. 9 is a configuration diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

FIG. 10 is a configuration diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

FIG. 11 is a configuration diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

FIG. 12 is a configuration diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

FIG. 13 is a structural explanatory view showing an embodiment of the main part of the projection type liquid crystal display device of the present invention.

FIG. 14 is a characteristic diagram showing an example of a main part of a projection type liquid crystal display device of the present invention.

FIG. 15 is a configuration diagram showing an embodiment of a projection type liquid crystal display device of the present invention.

FIG. 16 is a principle diagram showing an embodiment of a main part of a projection type liquid crystal display device of the present invention.

[Explanation of symbols]

1 light source 2 lighting means 3
Liquid crystal light valve 4 Projection means 5 Ellipsoidal mirror 6
Spherical mirror 7 Condenser lens 8 Field lens 9
Screen 10 Lamp 11 Electrode 1
2 Thermal insulation film 13 Arc tube 14 Lead wire 1
5 Foil 16 Base 17 Light emitting part 1
8 Optical Axis 19 Case 20 Incident Side Polarizer 2
DESCRIPTION OF SYMBOLS 1 Emission side polarizing plate 22 Prepolarizer 23 Heat ray cut filter 24 to 27 Dichroic mirror 28,2
9 Total reflection mirror 30 Casing 31 Speaker 3
2 power supply circuit 33 blow-out duct 34 blow-out fan 3
6 Presser plate 38 Leaf spring 39 Vent hole 4
0 folder 41 glass plate 43 video signal circuit 4
4 color separation synthesis unit 45 Suction duct 46 Suction fan 47 Liquid crystal light valve cooling outlet 48 Power circuit cooling outlet 49 Video signal circuit cooling outlet 50 Pre-polarizer-cooling outlet 51 Vent hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inoue Hisao Inage, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Inside the Hitachi Media Visual Media Laboratory (72) Inventor Takesuke Maruyama 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Visual Media Research Center

Claims (7)

[Claims] 1. An illuminating device having a light source, which has a function of irradiating light emitted from the light source onto a surface to be illuminated, a liquid crystal display element for modulating the light, and projecting the light emitted from the liquid crystal display element. In a projection type liquid crystal display device having a projection means,
The illumination means has at least an ellipsoidal mirror and a spherical mirror,
In addition, the projection type liquid crystal display device is characterized in that the liquid crystal display element is installed in the vicinity of a focus position farther from the light source which the elliptical surface of the ellipsoidal mirror has. 2. A projection type liquid crystal display device according to claim 1, wherein convex lenses are provided between the light source and the liquid crystal display element and between the liquid crystal display element and the projection means, respectively. 3. The light source is a lamp that emits light by a discharge between a pair of electrodes, and a lamp other than glass is provided on a straight line connecting the center between the electrodes and an arbitrary point on the reflecting surface of the spherical mirror. 3. The projection type liquid crystal display device according to claim 1 or 2, wherein there is no one having a function of diffusing or blocking light such as the diffusion film or the light shielding film. 4. The projection type liquid crystal display device according to claim 1, wherein the ellipsoidal mirror and the spherical mirror are arranged with one member interposed therebetween. 5. The light source is a lamp that emits red, green, and blue color lights, and the light source is provided between the illumination means and the three liquid crystal display elements that modulate the respective color lights emitted from the light source. Color separation means having a function of guiding each color light emitted from the light source to a liquid crystal display element corresponding to each color light is provided, and the color separation means is provided between the liquid crystal display element and the projection means.
5. The projection type liquid crystal display device according to claim 1, further comprising color synthesizing means for synthesizing color light emitted from one liquid crystal display element. 6. The illumination means and the projection means are arranged such that their optical axes are parallel to each other. The projection type liquid crystal display device according to claim 5. 7. In the projection type liquid crystal display device, a color separation / combination unit including at least the color separation means, the liquid crystal display element, and the color combination means is provided with respect to an optical axis of the illumination means and the projection means. A power supply circuit and a video signal circuit are arranged, a suction duct and a suction fan are arranged below the color separation / synthesis unit, and a blowing duct is provided on the surface side of the lighting means parallel to the optical axis of the lighting means. A blower fan is provided, and three liquid crystal display elements are provided in which the suction fan draws in wind from the outside on the opposite side of the color separation / combination unit of the suction fan to modulate the red, green, and blue color lights by the suction duct. And a device for displaying the wind by the blowing fan through the blowing duct by sending the wind to the lighting means, the power supply circuit and the signal circuit. Projection type liquid crystal display device of externally as blown into, characterized in that to constitute a flow path of the wind claim 5 or claim 6 wherein, the.