JPH11167093A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a display device which can be miniaturized by using a small-sized cooling fan, in which an incident side polarizing plate is efficiently cooled, which is made light, thin, short and small and which obtains high emitted luminous flux by constituting the device so that both back and front surfaces of the incident side polarizing plate of a liquid crystal light valve are cooled with the current of air from below by the cooling fan. SOLUTION: The liquid crystal light valve 3R is fastened on the liquid crystal light valve plate 11R by a screw, the light valve plate 11R is fastened on a guide plate 6R by the screw, and the plate 6R is fastened on an up plate 14 by the screw, so that the light valve 3R is held. As for the light valve 3R, the light incident side polarizing plate 12R is stuck to the surface of the plate 6R on a prism 4 side and a light emitting side polarizing plate 13R is stuck to the prism 4. The current of air generated by the cooling fan 7 is converged on a ventilation hole 9R, takes away the heat of the surfaces of the polarizing plates 12R and 13R, and blows upward from a hole formed on the plate 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a projection type display device for enlarging and projecting an image formed by a liquid crystal light valve by a projection lens.

[0002]

2. Description of the Related Art Conventionally, as shown in an external side view of an optical system unit in FIG. 7, for example, a liquid crystal light valve 3B is mounted on a flat guide plate 19B, and the guide plate 19B is fixed by a prism fixing plate 20 and a base 21. A display device using an optical system unit provided with a cooling means 22 below the optical system is known.

[0003]

However, in the conventional optical system unit, when a cooling fan is used as a cooling means, for example, as a cooling means, wind is generated as shown by arrows in FIG. 8 and the liquid crystal light valves 3B and 3R are generated. The wind flows on the surface of the incident side polarizing plate attached to the liquid crystal light valve 3B,
Although the incident-side polarizing plate attached to 3R was cooled, the cooling efficiency was low because the incident-side polarizing plate was attached to the liquid crystal light valve.

[0004] In order to improve the cooling capacity in this cooling efficiency, it is necessary to increase the cooling capacity of the cooling fan, and the cooling fan must be increased in size, which leads to an increase in the size of the display device. Further, when the cooling fan is used at the conventional cooling efficiency without increasing the size, there is also a problem that it is difficult to improve the emitted light flux of the display device due to this.

Accordingly, the present invention is to solve such a problem. An object of the present invention is to provide a projection type display device which maximizes the cooling capacity of a cooling fan, is light, thin and short, and has a high emission light flux. To provide. Still another object is to efficiently cool a polarizing plate that is vulnerable to temperature.

[0006]

In order to solve the above-mentioned problems, a projection display apparatus according to the present invention comprises a liquid crystal light valve for modulating light emitted from a light source, and a light modulated by the liquid crystal light valve. And a projection optical unit for projecting the liquid crystal light valve, the liquid crystal light valve is arranged with a gap between the incident side polarizing plate and the liquid crystal light valve, and a cooling fan is provided for the incident side polarizing plate. It is characterized in that wind for cooling the front and back surfaces is sent from below.

[0007]

According to the above arrangement, the back surface of the incident side polarizing plate of the liquid crystal light valve can be cooled by the cooling fan. In particular, since the incident-side polarizing plate is disposed with a gap from each liquid crystal light valve, both the back surface and the front surface of the hottest incident-side polarizing plate can be cooled.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view illustrating a basic configuration of an embodiment of the present invention. In FIG. 1, light emitted from a light source 1 is split into five primary colors of red, green and blue by a mirror having selective reflection characteristics in an optical waveguide 2 which is an example of an optical system means, and is guided. After being subjected to electro-optic modulation corresponding to each color by the light valves 3R, 3G, 3B, they are combined by the prism 4 and enlarged and projected on the front screen by the projection lens 5.

The liquid crystal light valves 3R, 3G, 3B are mounted and fixed to guide plates 6R, 6G, 6B each having a window at the center and a wind guide structure at a lower portion for secure fixing and adjustment. . The cooling fan 7 is attached to the lower part of the liquid crystal light valves 3R, 3G, 3B and the prism 4, and cools the polarizing plates related to the liquid crystal light valves 3R, 3G, 3B by spraying from below. The base 8 is
It has a shape capable of completely including the cooling fan 7, and has a ventilation hole on the upper surface thereof at a position relative to the air guide structure of the guide plates 6R, 6G, 6B (shaded portion in FIG. 1). FIG. 2 is an external side view of the optical system unit in the embodiment of the present invention, and FIG. 3 is a longitudinal sectional view taken along the optical axis AA in the figure. In FIG. 3, the description will be made only for the liquid crystal light valve for red 3R and its peripheral structure, but the structure is exactly the same for the peripheral structure of the liquid crystal light valve for green 3G and the liquid crystal light valve for blue 3B. Liquid crystal light valve 3R
Is fixed to the liquid crystal light valve plate 11R by screws, the liquid crystal light valve plate 11R is fastened to the guide plate 6R by screws, and the guide plate 6R is fastened to the up plate 14 by screws. In the liquid crystal light valve 3R, it is necessary to arrange polarizing plates 12R and 13R before and after the liquid crystal light valve 3R for displaying an image. In this example, the polarizing plate 12R on the light incident side with respect to the liquid crystal light valve 3R is connected to the guide plate 6R. Paste on the prism 4 side,
Polarizing plate 13 on the light emission side with respect to liquid crystal light valve 3R
Attach R to prism 4. The guide plate 6R has a window 15R for light incidence at the center, and a wind guide structure 10 below the window 15R.
R. On the other hand, the base 8 not only includes the cooling fan 7 but also holds the prism 4 with the up plate 14 and holds the liquid crystal light valve 3R held by the up plate 14 and its peripheral structure.

The base 8 also has a ventilation hole 9R at a position relative to the air guiding structure 10R on the upper side, and converges the wind generated by the cooling fan 7 to the ventilation hole 9R. The wind converged on the ventilation hole 9R is divided into a wind blowing right above and a wind trying to escape from the center of rotation of the cooling fan 7, and the former is between the liquid crystal light valve 3R and the exit-side polarizing plate 13R and the liquid crystal. The heat passes through the space between the light valve 3R and the incident-side polarizing plate 12R, removes heat from the surfaces of the polarizing plates 12R and 13R, and blows out above a hole provided in the up plate 14. The latter is a guide plate 6
The direction is changed to the direction of the polarizing plate 12R by the wind guide structure 10R provided in R, the heat of the surface of the polarizing plate 12R is removed through the central light entrance window 15R of the guide plate 6R, and the direction is changed by the polarizing plate 12R. Can be changed and blow out to the outside. FIG. 4 schematically shows the flow of these winds. The light incident side polarizing plate 12R absorbs about 60% of the heat of light due to its polarizing action and the surface temperature particularly rises. However, as described above, the polarizing property is improved by efficiently cooling the front and back surfaces. Damage can be prevented. In recent years, as the demand for display devices that are light, thin, small, and has a high emission light flux has increased,
This example in which the polarizing plate of the liquid crystal light valve is efficiently cooled by the small cooling fan is more and more effective.

[0011] In the future, as display devices become more and more light and compact,
Instead of the base 8 of this example shown in FIG. 5, a thin base 16 as shown in FIG. 6 is used, the cooling fan 18 is cut off from the lower part of the liquid crystal light valve, and the cooling fan 18 When the wind is sent from the lens direction to the base 16,
A wind flow similar to that in this example is conceivable, which is very effective in reducing the size and weight of the display device.

[0012]

According to the present invention, as described above, the cooling fan is used to cool both the back surface of the incident-side polarizing plate of the liquid crystal light valve with the wind from below, so that a small cooling fan is used. As a result, a miniaturized device can be realized, and the incident-side polarizing plate can be efficiently cooled, and a display device with a high outgoing luminous flux can be realized with a small size and a small size.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is an external side view of an optical system unit according to the embodiment of the present invention.

FIG. 3 is a longitudinal sectional view in FIG. 2;

FIG. 4 is a schematic diagram showing a flow of wind.

FIG. 5 is a schematic view of a base in the embodiment of the present invention.

FIG. 6 is a configuration diagram of a base and a cooling fan in another embodiment.

FIG. 7 is an external side view of a conventional optical system unit.

FIG. 8 is a schematic diagram showing a flow of wind in a conventional optical system unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Optical waveguide 3R, 3G, 3B ... Liquid crystal light valve 4 ... Prism 5 ... Projection lens 6R, 6G, 6B ... Guide plate 7 ... Cooling fan 8 Base 9R, 9B Ventilation hole 10R, 10B Ventilation structure 11R, 11B Incident side polarizing plate 12R, 12B Outgoing side polarizing plate 14 Up plate 15R , 15B ... entrance window

[Procedure amendment]

[Submission date] October 15, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

In order to solve the above-mentioned problems, a projection display apparatus according to the present invention comprises a liquid crystal light valve for modulating light emitted from a light source, and a light modulated by the liquid crystal light valve. And a projection optical unit for projecting the liquid crystal light valve, the liquid crystal light valve is arranged with a gap between the incident side polarizing plate and the liquid crystal light valve, and a cooling fan is provided for the incident side polarizing plate. It is characterized in that wind for cooling the front and back surfaces flows upward from below.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

[0012]

As described above, according to the present invention, since the cooling fan cools both the back surface of the incident side polarizing plate of the liquid crystal light valve by the wind from below, the heated cooling air is cooled. Since it rises from below and exits upward, it is possible to realize a miniaturized device by using a small cooling fan, and it is also possible to efficiently cool the incident-side polarizing plate, and to make it small, thin, short, A display device can be realized.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09F 9/00 360 G09F 9/00 360Z H04N 5/74 H04N 5/74 K

Claims (1)

[Claims] 1. A projection display apparatus comprising: a liquid crystal light valve for modulating light emitted from a light source; and projection optical means for projecting light modulated by the liquid crystal light valve. A projection type, wherein a side polarizing plate is arranged with a gap with the liquid crystal light valve, and a cooling fan is used to send wind for cooling the front and back surfaces of the incident side polarizing plate from below. Display device.