JP2003066408A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower an operation temperature of a liquid crystal panel and to improve reliability by more efficiently dissipating heat generated by the liquid crystal panel of an optical prism unit. SOLUTION: A silicone resin 35 as an adhesive with high thermal conductivity is filled between a panel holding frame 27 and the liquid crystal panel 24 and, at the same time, an identical silicone resin 35 is filled between a side face of a transparent glass substrate 28 and a heat radiating fin 31. By sticking the liquid crystal panel 24 and the panel holding plate 27 to each other, and the transparent glass substrate 28 and the heat radiating fin 31 to each other, and by using this kind of silicone resin 35, air of low thermal conductivity is completely excluded from the stuck faces. The heat generated by the liquid crystal panel 24 is efficiently dissipated and the liquid crystal panel 24 is cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector provided with an optical prism unit using a liquid crystal panel that modulates light according to a video signal.

[0002]

2. Description of the Related Art A liquid crystal projector using a liquid crystal panel that modulates light according to a video signal in order to obtain a large-sized video screen is known. A conventional liquid crystal projector is provided with an optical prism unit in which liquid crystal panels are respectively arranged on three surfaces of a dichroic prism, and each color luminous flux (R, G, B) after being modulated by the liquid crystal panel is color-synthesized by a dichroic prism, The projection lens projects the image onto a screen installed at a predetermined position.

In addition, in the conventional liquid crystal projector, the projection images from the respective liquid crystal panels are accurately superimposed on the screen, that is, so-called registration adjustment, so that the pixels on the respective liquid crystal panels can be aligned so that the pixels can be aligned left and right.
It has a vertical and rotational adjustment mechanism. Further, in order to focus the projected image on the screen clearly, a focus adjustment mechanism for the front-back, vertical and yaw directions is provided.

Further, along with the demand for miniaturization of the liquid crystal projector, miniaturization of the optical prism unit is required. However, in the case of the optical prism unit in which the adjusting mechanism is integrated as described above, when the liquid crystal panel becomes a certain size or smaller, it is difficult to downsize the adjusting mechanism attached thereto. Also, the finer the adjustment mechanism, the larger the size. Therefore, even if the liquid crystal panel is downsized, it is restricted by these adjusting mechanisms, and there is a structural limit to downsizing the optical prism unit in which these adjusting mechanisms are integrated.

Conventionally, for the purpose of downsizing, it has been devised that these adjusting mechanisms are omitted and the liquid crystal panel is directly adhered and fixed to the dichroic prism. Further, in order to facilitate replacement of the liquid crystal panel when a defect occurs, it has been proposed to omit the adjustment mechanism from the optical prism unit, attach a liquid crystal panel holding frame to the dichroic prism, and fix the liquid crystal panel to this.

[0006]

However, as the size and definition of the liquid crystal panel become smaller, the density of the amount of light incident from the light source increases, and the operating temperature of the liquid crystal panel tends to increase. That is, in the optical prism unit, the liquid crystal panel serves as a heat generation source. However, since the liquid crystal panel and the polarizing plate arranged on the emission side of the liquid crystal panel are both made of an organic material, it is very important to reduce the temperature of them in order to improve reliability. .

Therefore, it is an object of the present invention to provide a liquid crystal projector in which the operating temperature of the liquid crystal panel is lowered by more efficiently radiating the heat generated by the liquid crystal panel of the optical prism unit, and the reliability is improved. .

[0008]

The liquid crystal projector of the present invention is a liquid crystal projector having an optical prism unit in which a liquid crystal panel is arranged on the light incident surface of a dichroic prism, and the light incident surface of the liquid crystal panel has a high thermal conductivity. It is characterized in that a glass substrate is attached, and a radiation fin is bonded to a side surface of the glass substrate via an adhesive having a high thermal conductivity.

According to the present invention, the heat generated by the liquid crystal panel is efficiently transmitted to the heat radiation fins through the glass substrate and the adhesive having high thermal conductivity, and is diffused from the heat radiation fins to the atmosphere. Further, in the present invention, since the side surface of the glass substrate is bonded to the heat radiation fin, the clearance on the light incident surface side of the glass substrate can be increased, and the adjustment width in the focus direction during registration adjustment can be secured. It's easy. Further, the clearance between the side surface of the glass substrate and the heat radiation fin can be made as small as possible so that the heat generated in the liquid crystal panel can be efficiently transmitted from the glass substrate to the heat radiation fin.

Further, the liquid crystal projector of the present invention is provided with a panel holding frame for holding the liquid crystal panel and transmitting heat of the liquid crystal panel to the heat radiation fins. The panel holding frame is provided from the side surface of the liquid crystal panel to the light emitting surface. It is characterized in that it is provided with a stepped portion that wraps around, and the stepped portion is filled with an adhesive having a high thermal conductivity for adhering the liquid crystal panel and the panel holding frame.

According to the present invention, since the contact area between the liquid crystal panel and the panel holding frame is expanded by the adhesive filled in the stepped portion of the panel holding plate, the heat generated by the liquid crystal panel has high thermal conductivity. The heat is efficiently transmitted to the panel holding frame via the, and further transmitted from the panel holding frame to the heat radiation fins, and is diffused into the atmosphere from the heat radiation fins.

Here, if the heat dissipation fin is provided with a parting portion that covers a part of the light incident surface of the liquid crystal panel and controls the incident light, a separate part is formed on the light incident surface side of the liquid crystal panel as in the conventional case. Eliminates the need for plates.

If the step portion also serves as a parting part that covers a part of the light emitting surface of the liquid crystal panel and controls the emitted light, a parting plate is separately provided on the light emitting surface side of the liquid crystal panel as in the conventional case. It becomes unnecessary to provide.

The thermal conductivity of the adhesive used in the liquid crystal projector of the present invention is preferably 1 to 3 W / mK. By bonding the glass substrate and the radiating fins or the liquid crystal panel and the panel holding frame with an adhesive having a thermal conductivity of 1 to 3 W / mK, heat transfer between them is most efficiently performed.

[0015]

1 is a diagram schematically showing an optical system of a liquid crystal projector according to an embodiment of the present invention, and FIG.
FIG. 2 is an exploded perspective view showing details of the optical prism unit 20 of FIG. 1.

The liquid crystal projector 1 shown in FIG. 1 includes a light source 2, an illumination optical system composed of integrator lenses 3 and 4, total reflection mirrors 5, 6, 7 and 10, and reflects red light and green light to produce blue light. A dichroic mirror 8 that transmits only light, a dichroic mirror 9 that reflects only green light, and a color separation optical system composed of condensing lenses 11, 12, 13, 14, and 15, mainly for blue, green, and red, respectively. It has an optical prism unit (color combining optical system) 20 including three corresponding liquid crystal panels 22, 23, 24 and a dichroic prism 21, and a projection lens (projection optical system) 16.

As shown in FIG. 2, the optical prism unit 20 has a panel holding frame 27 attached to each of three light incident surfaces of a dichroic prism 21 sandwiched by upper and lower plates 25 and 26, and a liquid crystal panel 22 ,.
23 and 24 are fixed respectively. A transparent glass substrate 28 is fixed on the incident surface side of the liquid crystal panel 24, and a polarizing plate 29 and a retardation plate 30 are fixed on the exit surface side.

The transparent glass substrate 28 is made of sapphire (thermal conductivity of about 36 W / mK) and spinel (thermal conductivity of 16 W / mK).
mK), a material having a high thermal conductivity such as quartz or neoceram, and having a high thermal conductivity with respect to the liquid crystal panel 24 (a thermal conductivity of about 1 to 3 W / mK and having a property of curing at room temperature). It is attached with a thermosetting transparent resin such as a colorless transparent liquid silicone gel adhesive or an ultraviolet curable resin. In addition, in this optical prism unit 20,
In order to efficiently radiate the heat generated in the polarizing plate 29 and the liquid crystal panel 24, the heat radiation fins 31 and 32 are fixed to the panel holding frame 27 by tightening the bolts 33. Radiating fin 3
1, 32 are aluminum with high heat conductivity (heat conductivity 2
40 W / mK), magnesium (thermal conductivity 156 W / m
K), copper (thermal conductivity 420 W / mK), silver (thermal conductivity 4
32 W / mK), black anodized aluminum, anodized magnesium, or the like. Although only one surface of the liquid crystal panel 24 is shown in FIG. 2 for simplification of description, all three surfaces of the optical prism unit 20 to which the panel holding frame 27 is attached have the same configuration.

FIG. 3 is a vertical sectional view showing details of the liquid crystal panel mounting portion of FIG. 2, and FIG. 4 is a perspective view of the panel holding frame 27. As shown in FIGS. 3 and 4, the panel holding frame 27
Is an opening 27a that guides the light emitted from the liquid crystal panel 24 to the dichroic prism 21, and a light emission surface from the side surfaces of the liquid crystal panel 24 (four peripheral surfaces other than the light incident surface and the light emission surface of the liquid crystal panel 24). 3 Step on the left side) 2
7b and. The step portion 27b is formed so as to cover the outer edge of the light emitting surface of the liquid crystal panel 24, and functions as a parting portion for partially blocking and controlling the light emitted from the liquid crystal panel 24. On the other hand, on the light incident surface side of the liquid crystal panel 24, a parting plate 34 is provided on the light incident surface of the transparent glass substrate 28 for partially blocking and controlling the light incident on the liquid crystal panel 24.

A silicone resin 35 is filled between the panel holding frame 27 and the liquid crystal panel 24 as an adhesive having a high thermal conductivity. Similarly, the same silicone resin 35 is filled between the side surface of the transparent glass substrate 28 and the heat radiation fin 31. The silicone resin 35 is
It has a heat transfer coefficient of about 1 to 3 W / mK and has a property of being cured at room temperature. Such a silicone resin 3
By bonding the liquid crystal panel 24 and the panel holding plate 27, the transparent glass substrate 28 and the radiation fins 31 by using 5,
Air having low thermal conductivity does not intervene between them, and the heat generated by the liquid crystal panel 24 can be efficiently transmitted. As the adhesive having a high thermal conductivity, it is possible to use an acrylic resin, an ultraviolet curable resin, or a resin having a thermosetting property in addition to the ultraviolet curability.

In the liquid crystal projector 1 having the above structure, the white light emitted from the light source 2 is color-separated into three primary colors of blue, green and red by the color separation optical system, and the corresponding liquid crystal panels 22, 23 and 24 respectively. The images are modulated to form a blue image, a green image, and a red image, respectively. The images formed by the liquid crystal panels 22, 23, 24 are combined by the dichroic prism 21, and the combined color image is formed by the projection lens 16.
The image is projected on the screen 17 installed at a predetermined position.

At this time, the liquid crystal panel 24 and the polarizing plate 2
The heat generated by 9 is divided into two systems from the panel holding frame 27 to the radiation fins 31 and from the transparent glass substrate 28 to the radiation fins 31, and is radiated into the atmosphere. Since heat is transferred between the liquid crystal panel 24 and the panel holding frame 27 and between the transparent glass substrate 28 and the heat radiation fins 31 through the silicone resin 35 having a high heat transfer coefficient, not through the atmosphere, the liquid crystal panel 2
4 and the polarizing plate 29 can be efficiently cooled, and their operating temperatures can be lowered.

Thus, the liquid crystal panel 24 and the polarizing plate 2
If the operating temperature of 9 is lowered, the life and reliability of the optical prism unit can be improved. Further, in the future, even if the liquid crystal panel 24 becomes smaller and higher definition and the amount of heat generation increases, the amount of heat radiation can be increased to cope with it. Further, since it is possible to suppress the number of rotations of the cooling fan that cools the liquid crystal panel 24 and the polarizing plate 29, it is possible to obtain a liquid crystal projector in which noise of the cooling fan is reduced and quietness is improved.

Further, the liquid crystal panel 24 and the panel holding frame 27
Means not only the side surface of the liquid crystal panel 24 but also the liquid crystal panel 24.
Since a part of the light emitting surface of the liquid crystal panel is adhered by the silicone resin 35, the heat transfer area from the liquid crystal panel 24 to the panel holding frame 27 is larger than that when only the side surface of the liquid crystal panel 24 is adhered. Can be cooled more efficiently. In addition, since the bonding area is large as compared with the case where only the side surface of the liquid crystal panel 24 is bonded, the holding force of the liquid crystal panel 24 of the panel holding frame 27 is strengthened, and the influence of external impact, internal thermal stress, etc. It is possible to prevent the liquid crystal panel 24 from being displaced due to.

Further, the panel holding frame 2 in this embodiment
Since 7 also functions as a parting plate on the emission surface side of the liquid crystal panel 24, it is possible to reduce the parting plate which is separately required in the conventional structure, and the number of assembling steps, the manufacturing cost of the parting plate, and the like. It is possible to reduce the assembly equipment and the like.

5 and 6 are vertical sectional views showing another example of the liquid crystal panel mounting portion. Here, the liquid crystal panel 24, the transparent glass substrate 28, the polarizing plate 29, the retardation plate 30, and the parting plate 34 are common to the above-described example. However, in the example shown in FIGS. 5 and 6, the silicone-based resin 3 is applied to the step portion of the panel holding frames 36 and 27 that hold the liquid crystal panel 24.
5 is different in that it has a sagging prevention part 5.

In the example shown in FIG. 5, a convex-concave portion 37 having a fine pitch and having a small pitch is provided as a sagging prevention portion on the light emitting surface side of the stepped portion of the panel holding frame 36. When fixing the liquid crystal panel 24 to the panel holding frame 36, it is necessary to apply the silicone-based resin 35 before the registration adjustment, but the silicone-based resin 35 applied by the convex and concave portions 37 shown in FIG. It is possible to prevent silicone resin from adhering to the light emitting surface of the liquid crystal panel 24.

In the example shown in FIG. 6, an intermediate member 3 such as an O-ring or packing is located between the panel holding frame 27 and the liquid crystal panel 24 and is closest to the opening of the panel holding frame 27.
8 are arranged. Here, the intermediate member 38 is assumed to have elasticity so that excessive force is not applied to the liquid crystal panel 24 when it contacts the liquid crystal panel 24. As a result, similarly to the above example, the dropping of the applied silicone resin 35 is prevented by the intermediate member 38.

FIG. 7 is a vertical sectional view showing another example of the liquid crystal panel mounting portion. Here, the liquid crystal panel 24, the panel holding frame 27, the transparent glass substrate 28, the polarizing plate 29, and the retardation plate 30 are common to the example of FIG. However, the example shown in FIG. 7 is different in that the parting plate 34 shown in FIG. 3 is not provided, and the heat dissipating fins 39, 40 are provided with parting parts 41, 42 for controlling incident light instead of the parting plate 34. To do.

Further, as shown in FIG. 7, the transparent glass substrate 28 and the radiation fins 39, 40 are bonded to each other on the side surface of the transparent glass substrate 28 with a silicone resin 35, and the transparent glass substrate 28 and the radiation fins 39, 40 are bonded. 40 parting part 4
A clearance for registration adjustment in the focus direction is secured between the first and second parts.

Since the radiation fins 39 and 40 also have the function of the parting plate 34 in this way, the incident surface side of the transparent glass substrate 28 is opened, so that the radiation efficiency from the incident surface of the transparent glass substrate 28 is improved. At the same time, the number of parts can be reduced and the number of assembling steps can be reduced. Further, it is possible to reduce the manufacturing cost of the parting board and the assembly equipment.

FIG. 8 is a longitudinal sectional view showing still another example of the liquid crystal panel mounting portion. Here, the bonding structure of the liquid crystal panel 24, the transparent glass substrate 28, the polarizing plate 29, the retardation plate 30, and the liquid crystal panel 24 and the radiation fins 43 and 44 is common to the example of FIG. However, in the example shown in FIG. 8, the panel holding frame 27 shown in FIG.
4 is adhered to the upper and lower plates 25 and 26 of the dichroic prism 21 with a silicone resin 35, respectively.

As described above, the liquid crystal panel 24 is adhered to the heat radiation fins 43 and 44 by the silicone resin 35 on the side surface of the transparent glass substrate 28, so that the panel holding frame can be eliminated as shown in FIG. Become. Further, in the example shown in FIG. 8, the radiation fins 43 and 44 coated with the silicone-based resin 35 are respectively moved from the vertical direction of 45 degrees and fixed at the contact position with the transparent glass substrate 28. At this time, if the pressure applied to the liquid crystal panel 24 is controlled, the clearance between the liquid crystal panel 24 and the transparent glass substrate 28 can be stably reduced, and the silicone resin 35 interposed between them can be reduced. The heat transfer can be performed more efficiently.

In this embodiment, the thermal conductivity is about 1 to 3 W / mK so that the heat can be transferred most efficiently between the panel holding frame 27 and the liquid crystal panel 24 and between the transparent glass substrate 28 and the radiation fins 31. Silicone resin 3
5 is filled, but the present invention is not limited to this, and in short, if heat transfer coefficient between them can be efficiently performed,
It can be applied even if the thermal conductivity is out of this range.

[0035]

According to the present invention, the following effects can be obtained.

(1) A glass substrate having a high thermal conductivity is attached to the light incident surface of a liquid crystal panel, and a radiation fin is adhered to the side surface of the glass substrate via an adhesive having a high thermal conductivity. The clearance between the side surface and the heat dissipation fin is made as small as possible, the heat generated in the liquid crystal panel is efficiently transmitted from the glass substrate to the heat dissipation fin, and the liquid crystal panel is cooled to lower its operating temperature. The life and reliability of the can be improved.

(2) A panel holding frame for holding the liquid crystal panel and transmitting heat of the liquid crystal panel to the heat radiation fins is provided, and the panel holding frame has a step portion that wraps around the side surface of the liquid crystal panel to the light emitting surface. The stepped portion is filled with an adhesive having a high thermal conductivity for bonding the liquid crystal panel and the panel holding frame, so that heat generated by the liquid crystal panel is transmitted from the panel holding frame to the heat radiation fins and from the side surface of the glass substrate to the heat radiation fins. Since the liquid crystal panel is further cooled, the service life and reliability of the optical prism unit can be improved.

(3) The heat radiation fin is provided with a parting portion that covers a part of the light incident surface of the liquid crystal panel and controls the incident light, thereby improving the heat radiation efficiency from the light incident surface of the glass substrate. Further, the liquid crystal panel can be cooled, and the number of parts can be reduced to reduce the number of assembling steps, the manufacturing cost of the parting plate, the assembling equipment and the like.

(4) The stepped portion covers a part of the light emitting surface of the liquid crystal panel and also serves as a parting portion for controlling the emitted light, thereby reducing the parting plate which is separately required in the conventional structure. Therefore, the number of assembling steps can be reduced.

(5) The thermal conductivity of the adhesive is 1 to 3 W / m.
Since it is K, the heat transfer between the glass substrate and the radiation fins bonded by this adhesive and between the liquid crystal panel and the panel holding frame is performed most efficiently, and further the liquid crystal panel is cooled to lower its operating temperature. You can

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an optical system of a liquid crystal projector according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing details of the optical prism unit shown in FIG.

3 is a vertical cross-sectional view showing details of a liquid crystal panel mounting portion of FIG.

FIG. 4 is a perspective view of a panel holding frame.

FIG. 5 is a vertical cross-sectional view showing an example of a liquid crystal panel mounting portion.

FIG. 6 is a vertical cross-sectional view showing an example of a liquid crystal panel mounting portion.

FIG. 7 is a vertical cross-sectional view showing an example of a liquid crystal panel mounting portion.

FIG. 8 is a vertical cross-sectional view showing an example of a liquid crystal panel mounting portion.

[Explanation of symbols]

1 LCD projector 2 light sources 3,4 integrator lens 5,6,7,10 Total reflection mirror 8,9 Dichroic mirror 11, 12, 13, 14, 15 Condensing lens 16 Projection lens 17 screen 20 Optical prism unit 21 Dichroic prism 22,23,24 Liquid crystal panel 25,26 plates 27,36 panel holding frame 28 Transparent glass substrate 29 Polarizer 30 Phase plate 31, 32, 39, 40, 43, 44 Radiating fins 33 volts 34 parting board 35 Silicone resin 37 convex and concave 38 Intermediate member 41,42 parting section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shizuo Nishihara             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Yoshifumi Akaike             2-3-3 Hyakudohama, Sawara-ku, Fukuoka-shi, Fukuoka               Within Sony Semiconductor Kyushu Corporation (72) Inventor Naoko Uno             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Michio Nagaya             2-3-3 Hyakudohama, Sawara-ku, Fukuoka-shi, Fukuoka               Within Sony Semiconductor Kyushu Corporation F term (reference) 2H088 EA14 EA68 KA30 MA16 MA20

Claims (8)

[Claims] 1. A liquid crystal projector including an optical prism unit in which a liquid crystal panel is arranged on a light incident surface of a dichroic prism, wherein a glass substrate having a high thermal conductivity is attached to the light incident surface of the liquid crystal panel. A liquid crystal projector characterized in that heat radiation fins are bonded to the side surface via an adhesive having high thermal conductivity. 2. A panel holding frame that holds the liquid crystal panel and transfers heat of the liquid crystal panel to the heat radiation fins, the panel holding frame having a step portion that wraps around a side surface of the liquid crystal panel to a light emitting surface. 2. The liquid crystal projector according to claim 1, further comprising: an adhesive having a high thermal conductivity for filling the liquid crystal panel and the panel holding frame. 3. The liquid crystal projector according to claim 1, wherein the heat dissipation fin includes a parting portion that covers a part of a light incident surface of the liquid crystal panel and controls incident light. 4. The liquid crystal projector according to claim 2, wherein the step portion also serves as a parting portion which covers a part of the light emitting surface of the liquid crystal panel and controls the emitted light. 5. The thermal conductivity of the adhesive is 1 to 3 W / m.
The liquid crystal projector according to claim 1, wherein the liquid crystal projector is K. 6. The thermal conductivity of the adhesive is 1 to 3 W / m.
The liquid crystal projector according to claim 2, wherein the liquid crystal projector is K. 7. The thermal conductivity of the adhesive is 1 to 3 W / m.
The liquid crystal projector according to claim 3, wherein the liquid crystal projector is K. 8. The thermal conductivity of the adhesive is 1 to 3 W / m.
The liquid crystal projector according to claim 4, wherein the liquid crystal projector is K.