JPH05950Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a projection type liquid crystal display device.

[Conventional technology]

A projection type liquid crystal display device, generally called a liquid crystal projector, projects light from a light source onto a transmissive liquid crystal display panel and projects the display image of the liquid crystal display panel onto a screen. Conventionally, a light source including a light source lamp and a reflector was placed at the rear of the case, a liquid crystal display panel was placed at the front of the case, and a projection lens was provided at the front of the case. It is being

Incidentally, in the above-mentioned projection type liquid crystal display device, a high-intensity, high-voltage discharge lamp such as a xenon lamp or a halogen lamp is used as the light source lamp, but since this type of lamp generates a considerable amount of heat, it is necessary to remove it from the light source. The temperature inside the case rises due to heat dissipation,
There is a problem in that this adversely affects the liquid crystal display panel, which is sensitive to heat. For this reason, conventionally, a partition wall with a transparent window that allows light from the light source to pass through is provided in the middle of the case, and this partition wall divides the inside of the case into the light source side and the display side. The radiant heat is blocked by the partition wall.

[Problem that the invention attempts to solve]

However, even in a projection type liquid crystal display device in which the inside of the case is divided into the light source side and the display side by a partition wall as described above, the partition wall has a transparent window to transmit light from the light source. A transparent plate such as glass installed in this transparent window absorbs radiant heat from the light source and raises its temperature, and heat radiation from this transparent plate raises the temperature of the display side, which increases the response speed of the liquid crystal display panel. There was a problem that it had a negative effect on deterioration.

This idea was created in view of the above-mentioned circumstances, and its purpose is to effectively suppress the temperature rise on the display side due to radiant heat from the light source, and to increase the temperature of the liquid crystal display panel. An object of the present invention is to provide a projection type liquid crystal display device that can reliably prevent thermal effects.

[Means to solve problems]

In this invention, the case of the display device is divided into a light source house that houses the light source and a display house that houses the liquid crystal display panel, and the light source is located on the opposite side of the light source house and the display house, respectively. The present invention is characterized in that a wall is provided with a transparent window that transmits light, and the light source house and the display house are connected to each other with a gap provided between the two wall bodies.

[Effect]

According to the projection type liquid crystal display device of this invention, walls are provided on the opposite sides of the light source part house and the display part house, and a gap is secured between the two walls, so that the light source part house side Even if the transparent plate of the transparent window installed in the wall absorbs the radiant heat from the light source and rises in temperature, the heat emitted from this transparent plate is greatly buffered and reduced by the gap. Therefore, it is possible to reduce the amount of heat that is absorbed by the transparent plate of the transparent window provided on the wall on the side of the display house and radiated into the display house. The radiant heat from the light source can be blocked by the wall on the side of the light source house, the outside air layer flowing through the outside air circulation gap, and the wall on the side of the display house. Effectively suppresses temperature rise on the display side due to heat in the light,
It is possible to reliably prevent thermal effects on the liquid crystal display panel.

〔Example〕

Hereinafter, one embodiment of this invention will be described with reference to the drawings regarding a projection type liquid crystal display device that projects television images onto an external screen.

1 and 2, reference numeral 1 indicates a case of a display device, and this case 1 is constructed by combining a pair of upper and lower case bodies made of heat-resistant resin. This case 1 is divided into two houses, front and rear, in the middle, with house 2 on the rear side serving as a light source house, and house 3 on the front side serving as a display house. Reference numerals 4 and 5 denote walls that are vertically provided on opposite sides of the light source house 2 and the display house 3 to completely close off the space between the light source house 2 and the display house 3; 4 and 5 are integrally formed with the case 1 from the same heat-resistant resin as the case 1. Transparent windows 6 and 7 having approximately the same area are formed in the center portions of both walls 4 and 5, respectively.
are formed by attaching transparent plates 6a, 7a made of heat-resistant glass or the like to openings provided in the walls 4, 5 to completely close the openings. The light source house 2 and the display house 3 are connected via a rectangular frame-shaped connecting part 1a integral with the case 1, with an outside air circulation gap 8 secured between the walls 4 and 5. Further, a plurality of ventilation holes 9, 9 for circulating outside air into the outside air circulation gap 8 are provided on the upper and lower sides and both side surfaces of the square frame-shaped connecting portion 1a.

On the other hand, 10 is a light source housed in the rear side of the light source house 2 facing the transparent window 6 of the wall 4. This light source 10 includes a high-intensity light source lamp 11 such as a xenon lamp or a halogen lamp. and,
The light source lamp 11 includes a reflector 12 that reflects the light from the light source lamp 11 toward a transmissive liquid crystal display panel 20 housed in the display house 3. Note that the reflector 12 is a parabolic reflector that reflects the light from the light source lamp 11 as parallel light. 13 is a power circuit board provided with a power transformer 14 and a transformer coil 15. This power circuit board 13 is provided in the light source house 2, and the light source lamp 11 is connected to the lead wires 16, 1.
6 to the power supply circuit board 13.
Further, reference numeral 17 denotes a polarization separation prism provided in the light source house 2 and located in front of the light source 10. This polarization separation prism 17 is a reflector 1
2, the light from the light source 10 reflected by the light source 10 is separated into ordinary light and extraordinary light. In this embodiment, the polarization separation prism 17 is used to allow the extraordinary light x to proceed straight, and the ordinary light y to pass through one side of the light source house 2. It uses something that refracts it toward the side. Reference numeral 18 denotes a plurality of ordinary light emission holes provided on one side of the light source house 2 and also serving as heat radiation holes. Further, a plurality of slit-shaped heat radiation holes 19, 19 are provided on the upper and lower surfaces, the other side surface, and the back surface of the light source house 2, respectively (the heat radiation holes on the lower surface are not shown), and the light source 10 emitted from the light source lamp 11 is The heat from these heat radiation holes 19, 1
9 and the ordinary light emission hole 18, heat is radiated to the outside.

21 is a display panel cooler provided in the display house 3 facing the transparent window 7 of the wall 5, and the liquid crystal display panel 20 is located in front of the display panel cooler 21 (the The center of the panel is aligned with the optical axis O of the parallel light from the light source 10, and is mounted substantially perpendicularly to the opposite surface. The display panel cooler 21 includes a pair of front and rear transparent plates (for example, glass plates) 22a, which are spaced apart and facing each other.
22b and a frame 22c that also serves as a heat sink and seals the outer periphery between the two transparent plates 22a and 22b. enters the liquid crystal display panel 20 through the display panel cooler 21. This liquid crystal display panel 20 is a TN type matrix display panel that displays television images (color images), and is provided with a polarizing plate 20a only on its front side. ing. The reason why the polarizing plate 20a is provided only on the front side of the liquid crystal display panel 20 is that the light from the light source 10 is converted into only the extraordinary light x by the polarization separation prism 17 and enters the liquid crystal display panel 20. , Therefore, even if a polarizing plate is not provided on the back side of the liquid crystal display panel 20, the same light as the light that has passed through the polarizing plate can be incident on the liquid crystal display panel 20, so the polarizing plate can be used as a liquid crystal display panel. It is sufficient to provide it only on the front side of 20. 24 is a condenser lens made of a circular Fresnel lens provided in the display house 3 facing the front of the liquid crystal display panel 20; 25 is a projection lens provided in the front of the display house 3; The light transmitted through the panel 20 is condensed onto a projection lens 25 by a condenser lens 24 . In addition, on the top and front surface of the display house 3,
A plurality of slit-like heat dissipating shapes 26, 26 are provided respectively.

Further, 27a and 27b are main circuit boards divided into two boards, and this main circuit board 2
A television linear circuit is constructed at 7a and 27b. This linear circuit obtains video signals, audio signals, and synchronization signals by amplifying and detecting an intermediate frequency tuned by a tuner (not shown, but attached to either the main circuit board 27a or 27b). This linear circuit is divided into two circuit parts and configured on both main circuit boards 27a and 27b. And both main circuit boards 27
a, 27b, the first main circuit board 27a
is housed in the light source house 2, the second main circuit board 27b is housed in the display house 3, and the main circuit board 27a in the light source house 2 is connected to the power supply circuit board 13 by a lead wire (not shown).
It is connected to the. The first main circuit board 27a and the second main circuit board 27b in the display house 3 are connected to vertically long terminal boards attached to the walls 4 and 5 of the light source house 2 and the display house 3, respectively. 28, 28 and a connector 30 that connects both terminal plates 28, 28. The terminal boards 28, 28 are formed by arranging a plurality of terminal pins 28a, 28a along the length of a vertically elongated insulating board, and these terminal boards 28, 28 are connected to the walls 4, 5, respectively. It is attached to the walls 4, 5 by closing the vertical openings 29, 29 provided in the walls 4, 5 on opposing surfaces without any gaps. Further, the terminal pins 28a, 28a of both the terminal boards 28, 28 protrude into the light source part house 2 and the display part house 3 from the vertically elongated openings 29, 29 of the walls 4, 5. , 28 terminal pins 28a, 28
a is connected to a first main circuit board 27a in the light source house 2 and a second main circuit board 27a in the display house 3 by lead wires 31, 31, respectively. Further, the connector 30 is
Terminal board connection parts 30a, 30a are provided at both ends of a flexible cable formed with a plurality of wires, and both terminal boards 28, 28 are connected to this connector 3.
0 terminal board connection parts 30a, 30a on both terminal boards 2
The terminal pins 8 and 28 are connected via a connector 30 by being fitted into and connected to the respective terminal pins 28a and 28a. Further, 32 is a display drive circuit board in which a display drive LSI chip 33 is attached to a flexible board.One end of this display drive circuit board 32 is connected to the second main circuit board 27a in the display house 3, The end is connected to a liquid crystal display panel 20.

The above-mentioned projection type liquid crystal display device causes light from a light source 10 to enter a transmission type liquid crystal display panel 20, and projects a display image of this liquid crystal display panel 20 onto an external screen (not shown) placed in front of the liquid crystal display device. The light from the light source 10 in the light source house 2 enters the polarization separation prism 17 and is separated into extraordinary light x and ordinary light y. Here, the ordinary light y refracted by the polarization separation prism 17 is transmitted through the ordinary light emission hole 1
The extraordinary light a that is emitted to the outside from 8 and passes straight through the polarization separation prism 17 is transmitted to the transparent window 6 of the wall 4 on the light source house 2 side and the wall 5 on the display house 3 side.
passes through the transparent window 7 and enters the display house 3,
The liquid crystal display panel 2 passes through the display panel cooler 21
0. Further, the light transmitted through the liquid crystal display panel 20, that is, the display image of the liquid crystal display panel 20, is focused by the condenser lens 24 onto the projection lens 25, and is enlarged and projected onto the screen surface by the projection lens 25. .

Therefore, in the projection type liquid crystal display device, the case 1 of the display device is divided into a light source house 2 housing the light source 10 and a display housing 3 housing the liquid crystal display panel 20. Walls 4 and 5 each having transparent windows 6 and 7 that transmit light from the light source 10 are provided on opposite sides of the light source house 2 and the display house 3, respectively.
Since the display section house 3 and the display section house 3 are connected by ensuring an outside air circulation gap 8 between the two walls 4 and 5, the transparent window 6 provided in the wall section 4 on the light source section house 2 side
Even if the transparent plate 6a absorbs the radiant heat from the light source 10 and rises in temperature, most of the heat emitted from the transparent plate 6a is transferred to the outside air circulation gap 8.
The heat is radiated to the outside through heat exchange with the outside air flowing through the display house 3, and is absorbed by the transparent plate 7a of the transparent window 7 provided on the wall 5 of the display house side 3. The amount of heat radiated into the interior can be reduced, and the radiant heat from the light source 10 can be transferred to the wall 4 on the light source house 2 side, the outside air layer flowing through the outside air circulation gap 8, and the display house 3.
Since it can be triple-blocked by the side wall 5, temperature rise on the display side due to radiant heat from the light source 10 or heat in the light can be effectively suppressed, and the temperature rise to the liquid crystal display panel 20 can be effectively suppressed. can reliably prevent thermal effects.

Moreover, in the above embodiment, the space between the light source house 2 and the display house 3 is completely closed off by the wall 4 on the light source house 2 side and the wall 5 on the display house 3 side. The first main circuit board 27a in the light source house 2 and the second main circuit board 27b in the display house 3 are attached to both walls 4, 5 with their openings 29, 29 closed without any gaps. Since the connection is made by the connector 30 via the plates 28, 28, the heat inside the light source house 2 does not leak to the display house 3 side, and therefore the temperature inside the light source house 2 can be raised more effectively. can be suppressed to Also. In the above embodiment, like a conventional liquid crystal display device, a polarizing plate is also provided on the back of the liquid crystal display panel 20, and light in a vibration direction unnecessary for display (ordinary light or extraordinary light) among incident light is polarized on the back side. Rather than cutting the light with a plate, the light from the light source 10 is passed through a polarization separation prism 17 in the light source house 2.
The light is separated into extraordinary light x and ordinary light y, and the light in the vibration direction that is unnecessary for display on the liquid crystal display panel 20 (ordinary light y in the embodiment) is emitted to the outside and is used for display on the liquid crystal display panel 20. Since only the light in the vibration direction to be used (abnormal light a in the embodiment) is taken into the display house 3 and made to enter the liquid crystal display panel 20, the liquid crystal display panel 2 is caused by the heat of the incident light.
0 temperature rise can also be lowered. In other words, if a polarizing plate is also provided on the back of the liquid crystal display panel and the light from the light source is directly incident on the liquid crystal display panel, the light in the vibration direction used for display and the light in the vibration direction unnecessary for display. Both of them enter the polarizing plate on the back side of the liquid crystal display panel, and this back polarizing plate cuts out unnecessary light in the vibration direction. In addition, the temperature will rise due to the heat of the light in the vibration direction that is unnecessary for display, but as in the above embodiment, only the display in the vibration direction used for display is placed inside the display house 3. Incorporated into the liquid crystal display panel 20
By making the light incident on the liquid crystal display panel 20, the temperature rise of the liquid crystal display panel 20 due to the heat of the incident light can be reduced to approximately half that in the case where unnecessary vibration direction light is also made incident on the liquid crystal display panel. Furthermore, in the above embodiment,
Since the light entering the display house 3 is made to pass through the display panel cooler 21 filled with the cooling liquid 23 and then enter the liquid crystal display panel 20,
The temperature of the light incident on the liquid crystal display panel 20 can be further lowered, and the liquid crystal display panel 20 is forcibly cooled by the display panel cooler 21. 2
0 temperature rise can be prevented.

In the above embodiment, the light source part house 2 and the display part house 3 are formed in the same case 1, and the light source part house 2 and the display part house 3 are connected by the connecting part 1a that is integrated with the case 1. , light source house 2
The case 1 may be divided into two parts and the display part house 3 may be made independent. In that case, the light source part house 2
and the display house 3 may be connected to each other by a suitable connecting member with their optical axes aligned. Furthermore, in the above embodiment, a projection type liquid crystal display device was described in which the display image of the liquid crystal display panel 20 is projected onto an external screen. It can also be applied to a projection type liquid crystal display device that projects a display image on a liquid crystal display panel. Furthermore, in the above embodiment, the light from the light source 10 is separated into ordinary light and extraordinary light by the polarization separation prism 17, and only the light in the vibration direction used for display on the liquid crystal display panel 20 is made to enter the liquid crystal display panel. However, without providing the polarization separation prism 17, a polarizing plate is also provided on the back side of the liquid crystal display panel 20, and light including ordinary light and extraordinary light from the light source 10 is made to enter the liquid crystal display panel 20. You can do it like this. Also,
The connection structure between the first main circuit board 27a in the light source house 2 and the second main circuit board 27b in the display house 3 is not limited to the above embodiment. Furthermore, the main circuit boards 27a and 27b are both connected to the light source house 2 or the display house 3.
In that case, the main circuit board may be integrated into one board.

[Effect of the invention] In the projection type liquid crystal display device of this invention, the case of the display device is divided into a light source house housing a light source and a display housing housing housing a liquid crystal display panel. Walls each having a transparent window for transmitting light from the light source are provided on the opposite side of the part house, and the light source part house and the display part house are connected by ensuring a gap between the two walls. Therefore, it is possible to effectively suppress temperature rise on the display section side due to radiant heat from the light source, and reliably prevent thermal effects on the liquid crystal display panel.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional plan view and an external view of a projection type liquid crystal display device showing an embodiment of this invention. DESCRIPTION OF SYMBOLS 1...Case, 1a...Connection part, 2...Light source part house, 3...Display part house, 4, 5...Wall body,
6, 7...Transparent window, 6a, 7a...Transparent plate, 8...
...Outside air circulation gap, 9...Vent hole, 10...Light source,
11...Light source lamp, 12...Reflector, 17
...Polarization separation prism, x...Extraordinary light, y...Ordinary light, 20...Liquid crystal display panel, 21...Display panel cooler.

Claims (1)

[Scope of utility model registration request] In a projection type liquid crystal display device in which light from a light source is incident on a liquid crystal display panel and a display image of the liquid crystal display panel is projected onto a screen surface, a case of the display device includes a light source house housing the light source and a liquid crystal display panel. The light source house is divided into a display house that accommodates a display panel, and walls each having a transparent window that transmits light from the light source are provided on opposite sides of the light source house and the display house, and the light source house and the display house are separated. 1. A projection type liquid crystal display device, characterized in that a display part house is connected to the display part house with a space provided between the two walls.