JP3398654B2 - Liquid crystal projector device and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light modulation device for performing light modulation using liquid crystal or the like and a liquid crystal projector device for synthesizing modulated lights for projection display. This belongs to the technical field of efficiently releasing the heat generated inside the optical system to the outside in order to achieve miniaturization.

2. Description of the Related Art Sapphire has a wide electromagnetic wave pass band from ultraviolet rays having a wavelength of 160 nm to infrared rays having a wavelength of 6 μm, and has a thermal conductivity of 42.0 (W / m · k) and 1.2 (W of quartz glass. / m ・ k), it was known as a material that shields heat through light. Also, the Vickers altitude is Hv2200 or higher, and the quartz glass Hv900
It is more than twice as hard. Young's modulus is 4.7 x 10
^-5 Mpa and quartz glass 7.2x10 ^-4 Mpa about 2
It is strong against bending because it is 1/0. In recent years, sapphire has attracted attention for its high optical transparency and high thermal conductivity.
In a conventional liquid crystal projector device, a polarizing plate to which a sapphire plate is attached is used, and a part of the light is shielded by the polarizing plate in the liquid crystal projector device to release the generated heat.

In the liquid crystal projector device, the polarizing plate blocks a part of the light, so that the heat generated by the change of the light energy is quickly transferred from the sapphire plate to the support and further to the housing. Need to escape. Therefore, it is necessary to increase the thermal conductivity between the sapphire plate and the support to keep the temperature around the liquid crystal low. However, in the conventional liquid crystal projector device, the sapphire plate and its supporting base are joined together by using an organic adhesive such as an acrylic UV-curable adhesive. Since the organic adhesive has a poor heat dissipation property as compared with the sapphire crystal, there is a problem that it is difficult to sufficiently dissipate the heat transmitted through the sapphire plate to the outside. Attempts have been made to dissipate the heat by using a gel-like substance that does not have adhesive properties, but this is still unknown in terms of reliability for consumer products. Therefore, a heat dissipation structure using a substance that is chemically and physically stable and has high thermal conductivity is desired. In addition, a metallization method using molybdenum / manganese has been proposed in the past. However, the processing method and the processing conditions in consideration of the temperature condition are not shown, and the proposed method cannot be realized.

In a liquid crystal projector device according to the present invention, a sapphire plate is attached to a polarizing plate to radiate heat applied to the polarizing plate, and the sapphire plate is fused to fix the sapphire plate. And a liquid crystal projector device having a sapphire plate support. The sapphire plate and the sapphire plate support can be improved in thermal conductivity by fusing and fixing the sapphire plate to the sapphire plate support so that heat can be quickly transferred from the sapphire plate to the sapphire plate support. A liquid crystal projector device according to the present invention is a liquid crystal projector device in which a joining pedestal metal is vapor-deposited on a fusion-bonding portion for fusion-bonding the sapphire plate. Since the joining base metal is vapor-deposited on the fusion portion, the fusion temperature can be freely controlled,
The fusion can be performed according to the usage environment of the liquid crystal projector device. The liquid crystal projector device according to the present invention,
In the liquid crystal projector device, the fused portion of the sapphire plate is frosted glass. The heat dissipation effect can be enhanced by rubbing the fused portion into a glass shape. In addition, the vapor deposition strength of the joining base metal can be increased. A method of manufacturing a liquid crystal projector device according to the present invention includes a sapphire plate supporting base that is a dry honed process for processing a sapphire plate into a frosted glass form, and a sapphire plate on which a bonding base metal processed into the frosted glass form is vapor-deposited. A method of manufacturing a liquid crystal projector device, comprising: Thus, by forming the frosted glass, the bonding pedestal metal can be strongly vapor-deposited, and the heat radiation effect between the sapphire plate and the sapphire plate support can be enhanced.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention comprises a step of processing the periphery of a sapphire plate processed into a double-sided mirror surface using a dry honing method into a glass-like periphery, and chromium, nickel, and The step of attaching the base metal for joining in the order of gold, the step of welding the support base made of a high thermal conductive material to the portion to which the base metal for bonding is attached with a low melting point metal, and the base It consists of the step of attaching a polarizing plate to the surface of the sapphire plate and the step of incorporating the sapphire part with the polarizing plate attached to the liquid crystal projector.

EXAMPLES Examples will be described with reference to the drawings. FIG. 1 shows a processing step of a liquid crystal projector device according to the present invention. In the present invention, first, a sapphire plate 10 whose both surfaces are mirror-polished is prepared (step 100). The length of the side of the sapphire plate varies depending on the size of the liquid crystal used, but is roughly classified into four types of 0.7 inch, 0.9 inch, 1.3 inch and 1.8 inch. The thickness of the sapphire plate can be higher if it is thin from the viewpoint of light transmittance, but considering physical strength, 0.5 mm is less than 0.9 inches and 0.7 mm is generally more than 1.3 inches. use. As for the crystal orientation of the sapphire plate surface, the A-plane [11-20] is used in consideration of the light transmittance.
The direction of the C-axis is 45 degrees with respect to each edge of the sapphire plate, and its azimuth accuracy is generally ± 1 degree. Further, in order to prevent the synthetic image from being distorted when the light-modulated image is magnified and projected, the processing accuracy of the sapphire plate is preferably 5 μm or less in both flatness and parallelism. The protective film paint 11 is applied to the entire surface of the prepared sapphire plate (step 10).
1). The protective film paint 11 serves as a protective film that protects the sapphire plate from scratches when the sapphire plate is adhered in the next step, and at the same time, the back-surface reflected light in the exposure step becomes stray light to expose the area other than the intended one. There is a purpose to prevent. Therefore, the color of the protective coating 11 is preferably black. Next, the sapphire plate 10 coated with the protective coating 11 on the entire surface is attached to the processing jig plate 12 using the fixing adhesive 18 (step 10).
2). This state is shown in FIG. FIG. 2 shows a jig plate 12 for processing.
It is a figure which shows the structure of. The back cover 17 is a jig plate 12 for processing.
Secure with screws. This is because the back cover 17 has the purpose of suppressing the outgas emitted from the protective film paint 11 and the fixing adhesive 18 when the vacuum is drawn in the vapor deposition machine. Since the sapphire plate 10 is peeled off from the processing jig plate 12 in the subsequent step (step 109), the fixing adhesive 18 is preferably an adhesive that dissolves in an organic solvent at room temperature so that it can be operated at room temperature. As shown in FIG. 2, the processing jig plate 12 has a hole on the back surface so that the organic solvent can easily permeate when the adhesive is peeled off. It is preferable that a shallow hole be engraved for positioning the sapphire plate 10 and the lithography mask 14 or the vapor deposition mask. Next, a film-shaped photoresist 13 is applied to the entire upper surface of the processing metal plate 12 to which the sapphire plate 10 is adhered (step 103),
The lithographic glass portion is exposed using a lithography mask 14 in which holes have been processed (step 104), and the exposed photoresist is washed away (step 105). FIG. 3 is a state diagram showing an exposure state. The film-like photoresist used here preferably has a thickness of 50 μm to 100 μm. This is because the dry honing in the next step is physical etching, and therefore, the photoresist is scraped off during the dry honing with a few μm which is used for a normal photoresist. Further, since the particles used for dry honing have variations in particle density, the photoresist needs to have a certain thickness that can withstand honing. On the other hand, if it is too thick, it will take time to strip the photoresist.
Next, dry honing is performed on the sapphire plate that has completed the exposure step (step 106). Table 1 shows the media and conditions for dry honing.

[Table 1] FIG. 4 shows a state in the dry honing machine and a state in which the periphery of the sapphire plate 10 is processed. Sapphire board 10
The protective film paint 11 is applied in advance to the side surface portion of the. This is because the medium hits the film-shaped photoresist 13 applied to the processing jig plate 12 and bounces off, so that the protective film paint 11 on the side surface of the sapphire plate 10 is peeled off, and the protective film paint 11 is removed. Sapphire is exposed at the peeled part. The media hits the exposed portion of the sapphire, and the portion of the sapphire plate 10 hit by the media is etched into a frosted glass. After completion of dry honing, the surface media is blown with compressed air, the photoresist is peeled off using a peeling agent, ultrasonic cleaning is further performed in alcohol for 5 minutes, and cold air drying is performed (step 1
07). The cleaning alcohol is preferably one that dries quickly and does not easily leave stains after drying, such as IPA or ethanol. Next, after the vapor deposition mask 15 is fixed to the sapphire plate 11 that has finished the honing process, it is placed in the vapor deposition machine 16 and the base metal 19 for bonding is vapor deposited in the order of chromium, nickel and gold (step 108). Table 2 shows the vapor deposition conditions of the joining base metal.

[Table 2] The unit of thermal conductivity is Cal · Cm ⁻¹ · S ⁻¹ · deg
^-1 . When gold is oxidized on the surface of gold and an oxide film is formed on the surface of gold, the oxide film lowers the thermal conductivity and hinders fusion with the low-melting-point metal 20. Therefore, gold is attached as an antioxidant film for nickel. For this reason, it is better to apply gold as thinly as possible. If it is made thin, the manufacturing cost can be reduced.
In step 106, since the protective coating material 11 on the side surface of the sapphire plate 10 is peeled off, the pedestal metal 19 for joining is attached to a part of the side surface of the sapphire plate 10 due to the wraparound of the vapor-deposited metal.
Is deposited. FIG. 5A shows a positional relationship between the sapphire plate 10 and the vapor deposition mask 15, and FIG. 5B is a state diagram showing a state after vapor deposition of the three kinds of joining base metals. The lithography mask 14 and the vapor deposition mask 15 can be used in common. In addition, without using steps 101 to 107,
When the vapor deposition mask 15 is directly covered on the sapphire plate 10 and the dry honing process is performed, the medium reaches the place where the frosted glass process is not performed, and the vapor deposition mask 15 is etched to change its shape.
It may become useless as 5. Next, the vapor deposition mask 15 and the back cover 17 are removed, and the resultant is placed in an organic solvent for peeling the adhesive, and the adhesive and subsequently the protective coating 11 are peeled off (step 109). Acetone is used as the organic solvent for peeling the adhesive. FIG. 6 shows the sapphire plate 10 removed from the processing jig. The bonding base metal 19 also adheres to the upper surface of the sapphire plate 10 exposed by the lithography mask 14 and the side surface of the sapphire plate 10 exposed from the processing jig plate 12. Non-reflective coating is performed on one surface of the sapphire plate 10 for the purpose of suppressing back surface reflection of the sapphire plate and preventing stray light due to back surface reflection (step 110). Anti-reflection coatings are roughly classified into single layer coats and multi-layer coats. In the liquid crystal projector device 22, the three primary colors of light (red, blue, green) are optically modulated for each primary color, and modulated light synthesis is performed after the optical modulation, so a single layer coat suitable for the wavelength band is sufficient, but a non-reflective coat. Is transparent and difficult to judge, so a multi-layer coat is generally used to prevent misuse. Moreover, the number of layers of the coat is generally three layers, and the reflectance is generally 1.5% or less.
Next, the sapphire plate is fused with the low-melting point metal 20 on the support 21 having a matt black surface except for the joint with the sapphire plate 10 (step 111). The material of the support 21 is preferably a metal having a high thermal conductivity, for example, pure copper or a copper alloy. The maximum ambient temperature is 40 degrees Celsius as the usage condition of the liquid crystal projector device 22.
70 degrees Celsius is the upper limit of the operation guarantee temperature of general TFT liquid crystal.
If the material of the support base 21 is pure copper or copper alloy,
The low melting point metal 20 is preferably solder. Generally, tin content is 5
The melting temperature of 0% solder is 150 degrees Celsius, 70 degrees Celsius
If the temperature is less than 100 degrees, it is possible to prevent problems caused by the sapphire plate coming off due to melting and the deterioration of the solder itself. Figure 7
Explaining in (a), the sapphire plate support 21 has two
Drill a stepped through hole. One outer shape of the through hole matches the outer shape of the sapphire plate 10, and the other outer shape is the inner circumference of the portion of the sapphire plate 10 to which the joining pedestal metal 19 is attached. And sapphire plate 1
The pedestal metal 19 for bonding adhering to the upper and side surfaces of
The sapphire plate support 21 and the sapphire plate 10 are fixed by fusing in step 111. Next, the support base 2
The polarizing plate 23 is pasted on the sapphire plate fused to 1 (step 112). This state is shown in FIG. At this time, the polarization plane of the polarizing plate 23 and the C axis of the sapphire plate 10 are oriented in the same direction so that the amount of passing light is maximized. Next, the sapphire plate support 21 is attached to an external heat dissipation plate 24 or a housing having a heat dissipation structure (step 113). This state is shown in FIG. The heat dissipation plate 24 is made of a material having a good heat dissipation property, for example, an aluminum die cast product. In addition, it is generally preferable to have many protrusions in order to obtain a large heat dissipation surface area. The shape of the heat dissipation plate 24 does not have to be these materials or shapes as long as it has heat dissipation properties. A case having a heat dissipation structure generally means a case in which a material having high thermal conductivity is used for the entire case and a device for obtaining a heat dissipation area is applied to the entire case.
FIG. 8 is a structural diagram showing a light modulation optical system using the liquid crystal 26, and shows the positional relationship between the polarizing plate 23 and the light modulation liquid crystal 26 in the liquid crystal projector device 22. The light emitted from the light source is split into the three primary colors of light, and then the incident side polarizing plate 2
When passing through 3, only the light having a specific plane of polarization is passed and the other lights are energy-converted into heat. This heat is transmitted from the sapphire plate 10 to the support 21 of the sapphire plate and radiated from the heat dissipation plate 24. That is, the light with the same plane of polarization reaches the liquid crystal 26. The light optically modulated by the liquid crystal 26 passes through the polarizing plate 23 on the emission side, shields light having different polarization planes generated at the time of light modulation, and emits modulated light having a uniform polarization plane. The light shielded by the polarizing plate 23 on the emission side also becomes heat, is transmitted from the sapphire plate 10 to the support base of the sapphire plate, and is radiated from the heat dissipation plate 24. The optical system shown in FIG. 8 corresponds to the three primary colors of light and has three systems of the same structure. It is devised that the heat generated in the polarizing plate 23 is efficiently transmitted to the heat dissipation plate 24. Further, forced air cooling by a cooling fan is a cooling method in which heat is dissipated by the flow of air. At this time, if the present invention is used together, a small cooling fan will suffice. Therefore, it is possible to suppress the noise caused by the forced air cooling.

The present invention is carried out in the form as described above, and has the following effects. By fusing the sapphire plate and fixing it to the sapphire plate support, the sapphire plate and the sapphire plate support can be improved in thermal conductivity, and the heat from the sapphire plate can be quickly transferred to the sapphire plate support. Can transfer heat. In addition, reliability during mass production can be improved. Since the bonding pedestal metal is vapor-deposited on the fused portion, the metal can be used to fuse the sapphire plate to the support of the metallic sapphire plate. The heat dissipation effect can be enhanced by rubbing the portion on which the bonding pedestal metal is vapor-deposited into a glass shape. In addition, the adhesion strength of the joint portion can be increased, and a mechanically strong structure can be obtained.

[Brief description of drawings]

FIG. 1 is a process drawing of a liquid crystal projector device.

FIG. 2 is a structural diagram of a processing jig plate.

FIG. 3 is a state diagram showing an exposure state.

FIG. 4 is a schematic view showing an example of dry honing processing.

5 is a state diagram showing a vapor deposition processing state, and FIG.
[Fig. 5] is a state diagram showing a positional relationship between a vapor deposition mask and a workpiece, and Fig. 5 (b) is a state diagram showing an attachment position of a joining base metal after completion of vapor deposition.

6A and 6B are state diagrams of a workpiece after vapor deposition processing, specifically, FIG. 6A is a side view and FIG. 6B is a front view.

FIG. 7 is a structural view showing a state in which a sapphire plate is fusion-bonded to a support base of the sapphire plate, FIG. 7 (a) is an enlarged view showing a positional relationship between the support base and the sapphire plate, and FIG.
FIG. 4 is a structural diagram including a heat sink.

FIG. 8 is a configuration diagram of a light modulation portion.

[Explanation of symbols]

10 sapphire plate 11 Protective film paint 12 Processing jig plate 13 Film type photoresist 14 Lithography mask 15 Evaporation mask 16 Evaporator 17 Metal plate back lid for processing 18 Fixing adhesive 19 Base metal for joining 20 Low melting point metal 21 Sapphire board support 22 Liquid crystal projector device 23 Polarizer 24 Heat sink 25 Anti-reflection coating 26 LCD

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ruriko Nakamura 6-41-6 Kameido, Koto-ku, Tokyo Morioka Seiko Industry Co., Ltd. (72) Kinra Sasaki 6-41-6 Kameido, Koto-ku, Tokyo Morioka Seiko Industry Co., Ltd. (56) Reference JP-A-6-337292 (JP, A) JP-A-2000-314809 (JP, A) JP-A-2001-42424 (JP, A) JP-A-2001-215491 (JP, A) ) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/13 505 G02B 5/30 G02F 1/1335 510 G03B 21/00 G03B 21/16

Claims (4)

(57) [Claims] 1. A liquid crystal projector device comprising: a sapphire crystal that is attached to a polarizing plate to radiate heat applied to the polarizing plate; and a sapphire crystal support that fixes the sapphire plate by fusing the sapphire crystal. 2. The liquid crystal projector device according to claim 1, wherein a bonding pedestal metal is vapor-deposited on a fusion-bonded portion that fuses with the sapphire crystal. 3. The liquid crystal projector device according to claim 1, wherein the fused portion of the sapphire plate is frosted glass. 4. A step of dry honing to process a sapphire crystal into a ground glass shape, a step of depositing a bonding base metal on the portion processed into the ground glass shape, and a step of depositing the bonding base metal. A method of manufacturing a liquid crystal projector device, comprising: a fusion step of fusing a sapphire crystal to a sapphire crystal support.