JPH11183038A - Heating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating furnace for uniformly heating a work, irrespective of its size. SOLUTION: The furnace has a heating position of a size enough to heat one work. This position is composed of heating sources 1a-1c capable of independent temp. settings. Or in addition to these independent temp. setting type source 1a-1c, temp. detecting means may be provided for independently controlling the heat sources 1a-1c, based on the temp. detection result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace particularly suitable for use in a process for producing a color filter for a liquid crystal display.

[0002]

2. Description of the Related Art In a process of manufacturing a color filter for a liquid crystal display, a photosensitive resin of a positive type or a negative type colored with a pigment or the like on a substrate, or a photosensitive resin is laminated on a colored non-photosensitive resin. The mainstream method is to apply the coating, dry and cure it in a heating furnace, and then process it into a desired pattern by photolithography. In addition, overcoating is often applied to the substrate surface after photolithography processing, dried and cured, and in the color filter manufacturing process, drying with a heating furnace,
The curing process occupies an important position.

There are various types of heating furnaces, such as a hot plate (hereinafter referred to as HP) system, a hot air oven system, and a vacuum drying system, and are appropriately selected according to the type and purpose of the resin.

In the HP method, an object to be heated is held directly on a plate heated by an electric heater or on a jig such as a pin installed on the plate, and is mainly heated by radiant heat transfer from the HP. This is a method of heating the body.

[0005] The hot-air oven system is a system in which hot air heated by an electric heater or the like is circulated in a heating furnace, and an object to be heated held in the furnace is heated mainly by convection heat transfer.

[0006] The vacuum drying method is a drying method in which an object requiring drying is held in a vacuum chamber and the inside of the chamber is decompressed to promote the evaporation of the solvent.

However, the conventional HP type heating furnace has the following problems.

When the object to be heated is heated while being held on the HP, a temperature difference occurs between the center and the end of the object to be heated. For example, the end of the object to be heated is close to the furnace wall without a heating source, and is likely to be lower in temperature than the center. In addition, a plurality of HP
In a heating furnace in which the object to be heated is sequentially heated and conveyed on the HP, the rear end of the object to be heated tends to be low in temperature in the first HP because of the influence of the outside air from the inlet. Furthermore, in the case of a heating furnace provided with a slow cooling zone, the front end of the body to be heated tends to be low in HP before the slow cooling zone.

If an HP which is sufficiently larger than the object to be heated is used,
Although it is possible to solve the above problem and keep the temperature of the end portion almost the same as that of the central portion, the size of the apparatus becomes large, and the initial cost and running cost increase.

Further, if an excessively large HP is used, the temperature of the end of the object to be heated is higher than that of the center, so if the size of the object to be heated is changed even if an appropriate HP size is selected. Therefore, a temperature difference occurs between the end and the center.

[0011] If the temperature difference between the central portion and the end portion of the object to be heated is large, the product quality varies, which is not preferable. For example, in the case of a photolithography process of a color filter for a liquid crystal display in which the present invention is particularly preferably used, if the temperature distribution of a glass substrate as a heating target spreads in a heating process before an exposure and a development process, a surface development in a subsequent development process may occur. This causes a serious problem in product quality, such as uneven development state in the product.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and to provide a heating furnace for uniformly heating the object to be heated regardless of the size of the object to be heated.

[0013]

The heating furnace and the method for producing a color filter according to the present invention which achieve the above objects are as follows.

(1) A heating furnace characterized in that a position for heating one object to be heated is constituted by a plurality of heating sources whose temperatures can be independently set.

(2) In addition to a plurality of heating sources capable of independently setting the temperature, a plurality of temperature detecting means are provided, and the temperature of each heating source is independently controlled based on the temperature detection result. The heating furnace according to the above (1), wherein

(3) The heating furnace according to (1) or (2), wherein the plurality of heating sources are one hot plate.

(4) The heating furnace according to (3), wherein the hot plate is provided with a heating source capable of independently setting a temperature at a center portion and an end portion.

(5) The hot plate is provided with a heating source and a temperature detecting means capable of setting the temperature independently at the center and at the end, and each heating source is independently controlled based on the temperature detection result. The heating furnace according to the above (3) or (4), wherein the temperature is controlled by heating.

(6) The heating furnace according to any one of (3) to (5), wherein the material of the hot plate is made of aluminum or metal whose surface has been subjected to ceramic treatment.

(7) A method for producing a color filter, comprising using the heating furnace according to any one of (1) to (6).

[0021]

Next, a preferred embodiment of the present invention will be described.

The heating furnace constituting the present invention is composed of one or a plurality of HPs. However, even if the heating furnace is applied to all or a particularly limited part of the plurality of HPs, the effect of the present invention is not impaired.

In the present invention, one object to be heated is simultaneously heated by a plurality of heating sources. As a method, a method of installing a plurality of heating sources inside one HP and one object to be heated are used. There is a method of arranging a plurality of HPs whose temperatures can be independently set at a position to be heated, and the method is not particularly limited.

The material of the HP is not particularly limited, but metals such as aluminum, iron, and copper, alloys of metals, and materials obtained by subjecting metals to surface treatment such as ceramics are preferably used.

The shape of the HP is not particularly limited, but it is preferable that the surface facing the object to be heated is flat. If it is not flat, there is a concern that the object to be heated cannot be heated uniformly due to the variation in the distance from the HP surface to the object to be heated.

The range of the heating temperature of the HP varies depending on the type and purpose of the object to be heated.
The temperature may be appropriately selected, such as 0 ° C. and room temperature to 350 ° C.

The material of the pins for holding the substrate is not particularly limited, but metals such as SUS, iron, copper, and brass, and heat-resistant polymer materials such as Vespel are preferably used.

The distance between the HP and the object to be heated is not particularly limited, but is preferably 2 to 50 mm, more preferably 3 to 1 mm.
0 mm, more preferably 5 to 8 mm. If the pin height is lower than the above value, the transport jig may be damaged by the contact between the heated object and the jig when the transport jig enters below the heated object. The distribution is poor, which is not preferable.

In the prior art, since one heated body is heated by a heating source with one temperature setting, it is easy to adjust the average ultimate temperature of the whole heated body. It is difficult to correct the temperature difference that occurs partially at the end and the like.

On the other hand, in the present invention, since one object to be heated is heated by a heating source with a plurality of temperature settings, not only the average attained temperature of the entire object to be heated but also a temperature difference occurring partially can be easily corrected. .

In addition, if a plurality of temperature detecting means are provided, and the temperature of each heating source is independently controlled based on the temperature detecting means, temperature correction becomes easier and the object to be heated can be made more uniform. Can be heated. Further, it is possible to correct the temperature variation of the HP generated when the object to be heated is mounted and not mounted, and to perform stable heating.

[0032]

EXAMPLES The present invention will be described based on examples, but the effects of the present invention are not limited by the examples.

FIG. 1 is a schematic view of a heating furnace used in Examples and Comparative Examples of the present invention. 1 is an HP, 2 is a reflection plate. 3
Is a pin for holding a glass substrate, and 4 is a glass substrate. The side surfaces 5 of the heating furnace, that is, the left and right sides viewed from the operation side are exhaust ports and are open. The gas heated in the furnace flows out from the exhaust port, and the gas at room temperature outside the furnace flows in. Therefore, the temperature near the exhaust port of the glass substrate, that is, the left and right sides when viewed from the operation side, tends to be low.

FIG. 2 is a schematic top view of the HP constituting the heating furnace of the embodiment, and shows the installation position of the glass substrate and the temperature measurement position.

FIG. 3 is a schematic view showing a temperature control mechanism of the HP constituting the heating furnace of the embodiment. In the present embodiment, a method of installing a plurality of heating sources inside one HP is adopted, and heating is performed using different heating sources in 1a, 1b, and 1c. In addition, the middle of the heating source which heats each part was shown typically as the boundary line of each part. In addition, 1b and 1c are controlled so as to have the same temperature by one temperature detecting means and one temperature controlling means.

FIG. 4 is a schematic top view of the HP constituting the heating furnace of the comparative example, showing the installation position of the glass substrate and the temperature measurement position.

FIG. 5 is a schematic view showing a temperature control mechanism of the HP constituting the heating furnace of the comparative example. In the comparative example, one H
P is controlled by one temperature detecting means and one temperature controlling means.

Example 1 An alkali-free glass substrate having a size of 300 × 400 mm ² was held in the apparatus shown in FIG. 2 for 300 seconds, and 10 mm from the center and the edge of the substrate shown in FIG.
Was measured using a TYPE-K thermocouple. The set temperature of the HP was set as shown in Table 1.

Comparative Example 1 Using the apparatus shown in FIG. 4, the set temperature of the HP was examined as shown in Table 1 in the same manner as in Example 1.

Example 2 Using the apparatus shown in FIG. 2, the set temperature of the HP was examined as shown in Table 2 in the same manner as in Example 1.

Comparative Example 2 Using the apparatus shown in FIG. 4, the set temperature of the HP was set as shown in Table 2, and the same study as in Example 2 was conducted.

[Comparison of Temperature Profiles] The temperature profiles of the central portion of the substrate and the edge portion of the substrate were compared.

Table 3 shows the temperature difference Δ between the ultimate temperature at the center of the substrate and the average ultimate temperature at the edge of the substrate after 300 seconds between the example and the comparative example.
T is shown. ΔT is a value obtained by subtracting the average temperature reached at the substrate end from the temperature reached at the center of the substrate. If it is positive, it indicates that the temperature is higher at the center, and if negative, it indicates that it is lower.

As shown in Table 3, in Comparative Example 1, the temperature at the substrate end was lower by 7 ° C. than that at the center, but in Example 1, it was reduced to 2 ° C. Similarly, in Comparative Example 2, the temperature at the substrate end was lower by 16 ° C., but in Example 2, the temperature was reduced to 5 ° C.

As described above, it was confirmed that the temperature difference between the central portion and the end portion of the substrate can be reduced by dividing the HP into the central portion and the end portion and controlling the temperature.

[0046]

[Table 1]

[Table 2]

[Table 3]

[0047]

According to the heating furnace of the present invention, since the temperature is controlled by dividing the HP into a central part and an end part, the temperature difference between the central part and the end part of the object to be heated, which was difficult to control with the prior art, A heating furnace which can be reduced in size and can uniformly heat the object to be heated can be provided.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a heating furnace used in Examples and Comparative Examples.

FIG. 2 is a schematic top view showing an example of an HP constituting the heating furnace of the present invention.

FIG. 3 is a schematic view showing an example of a temperature control mechanism of an HP constituting the heating furnace of the present invention.

FIG. 4 shows H constituting a conventional heating furnace used as a comparative example.
It is an upper surface schematic diagram which shows an example of P.

FIG. 5 shows H constituting a conventional heating furnace used as a comparative example.
It is the schematic which shows an example of the temperature control mechanism of P.

[Explanation of symbols]

 1a to 1c: HP 2: Reflector 3: Proxy pin 4: Glass substrate 5: Side of heating furnace (open state)

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Satoshi Tanaka 1-1-1 Sonoyama, Otsu City, Shiga Pref.

Claims (7)

[Claims] 1. A heating furnace wherein a position having a size for heating one heated object is constituted by a plurality of heating sources whose temperatures can be independently set. 2. A plurality of temperature detecting means are provided in addition to a plurality of heating sources whose temperatures can be set independently, and each of the heating sources is independently temperature-controlled based on a result of the temperature detection. The heating furnace according to claim 1, wherein: 3. The heating furnace according to claim 1, wherein the plurality of heating sources are one hot plate. 4. The heating furnace according to claim 3, wherein the hot plate is provided with a heating source capable of independently setting a temperature at a center portion and an end portion. 5. A hot plate is provided with a heating source and a temperature detecting means capable of independently setting a temperature at a center portion and an end portion, and independently controls each heating source based on the temperature detection result. 4. The apparatus according to claim 3, wherein the temperature is controlled.
Or the heating furnace according to 4. 6. The heating furnace according to claim 3, wherein the material of the hot plate is aluminum or a metal whose surface has been subjected to a ceramic treatment. 7. A method for producing a color filter, comprising using the heating furnace according to claim 1.