JPH0753066Y2 - Dx contact material - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention is a device for a camera, which is capable of electrically connecting a D-X contact member, particularly a chrome-plated electrode of a film cartridge, with low stress and high reliability. The present invention relates to an X contact member.

(Prior Art) A DEX contact for a camera (hereinafter referred to as a DX contact) detects a DEX code (hereinafter referred to as a DX code) provided on a film and sends the information to a processing circuit of the camera body. Connection element. This DX code is ISO
A camera automatic detection code consisting of information such as sensitivity, number of films, exposure area, etc., and a raster pattern in which the content of the film manufacturer, product category, information such as the number of shots, etc. It consists of a latent image barcode and so on. More than four years have passed since the commercialization of the Eastman Kodak Company in the United States for the first time in 1984 with this DX coded film, and DX code compatible cameras and lab equipment have become widely used in Japan.

Then, this DX cord is formed on the surface of a steel plate cartridge and consists of a checkered chrome-plated electrode.
The contact point electrically detects this code information and sends it to the inside of the camera to automatically set the ISO sensitivity of the used film, display the number of remaining films and the remaining number of films, auto return, end warning, exposure area setting, etc. . The number of DX contact members used for the DX contacts per camera is 6 to 9 for single-lens reflex cameras and 3 to 4 for compact cameras.

In addition, these multiple DX contact members are arranged in series in parallel with the direction of approach of the cartridge, but regarding this DX contact member, when the cartridge enters the DX contact member while being pressed against it, the DX contact member It does not get caught, the electrical contact is reliable, it easily returns even if it is pressed continuously, 0.5 mm between the trunk and the collar of the Patrone
Since there is a level difference, it is required that the stroke of 0.7 mm or more is possible.

(Problems to be solved) However, in the conventionally known DX contact member, as shown in FIG. 4, a hemispherical contact element 11 having a gold-plated surface formed by press-molding a metal round bar of brass or the like is used. Gold plated leaf spring
A connector having a vertical stroke is used, which is connected to the printed circuit board 13 via 12. However, this connector is expensive because gold plating must be used to ensure electrical contact, and to achieve stroke behavior, hemispherical metal contact elements 11 per contact,
Since it uses two parts, the gold-plated leaf spring 12, the number of parts is large, and there are drawbacks such as a large number of assembly steps for connecting the contact element and the leaf spring and between the leaf spring and the printed circuit board by soldering. is doing.

For this reason, there is a need for an integrally-molded type DX contact member that does not require gold plating and has only one component, and is easy to assemble. Currently, it is a conductive silicone rubber that is commonly used for calculators, telephones, keyboards, remote controllers, etc. Integral molding using a flexible contact member has low rubber hardness (D-type durometer hardness according to ASTM D2240 <20 degrees), so the self-cleaning effect (dirt or oxide film on the contacted surface is a characteristic of metal contacts) It has no effect of being removed when rubbing against the element), and dust is easy to adhere to and difficult to remove. In addition to lacking reliability of electrical connection, it lacks the high-class feeling necessary for a camera, and there is no good method so far. The current situation.

(Means for Solving the Problem) The present invention relates to an integrally-molded type DX contact member which solves such a problem, and has a D-type durometer hardness (ASTM D 2240) of 40 degrees or more. Characterized in that a conductive connector having a hard resin or a hard elastomer as a base material penetrates an insulating rubber base material, and the insulating rubber base material supports and floats the conductive connector. To do.

That is, the present inventors have conducted various studies to develop a DX contact member that does not require gold plating, has a small number of parts, and can be easily assembled. As a result, the metal contact of the connector used in the conventionally known DX contact has been investigated. If the conductive connector with hard resin as the base material is penetrated into the insulating rubber base material and the conductive connector is supported and floated by the insulating rubber base material, naturally gold plating is unnecessary. However, it was found that the number of parts is small and it is easy to assemble, and that this product also makes the electrical connection particularly reliable, and the types of hard resin and insulating rubber base material used here , We proceeded with the research on physical properties, etc., and added the conductive material such as carbon black and metal particles to this hard resin to make it a conductive one with a volume resistivity of 10 ° to 10 ² Ωcm. Goodbye However, regarding this, the D-type durometer hardness is 40 in order for the connector molded with this resin to have a texture like a plastic key top and to have a self-cleaning effect when it comes into contact with the electrode. We confirmed that it is preferable to use silicone rubber for this insulating rubber base material in terms of electrical characteristics, durability, and moldability, and completed the present invention. It was

This will be described in more detail below.

(Operation) The DX contact member of the present invention is, for example, as shown in FIG.
Type durometer Hardness of 40 degrees or more Conductive connector made by molding conductive resin by adding conductive material to hard resin 1
To the insulating rubber base material 2 formed into a dome shape 3,
The electrically conductive connector 1 is supported and floated by an insulating rubber base material 2, which may be sandwiched between a printed circuit board 4 and a camera housing 5 as shown in FIG. The second is the practical automatic camera detection code.
As shown in the figure, the upper end of the conductive connector 1 in the DX contact member shown in FIG. 1 should be brought into contact with the chrome-plated electrode 7 of the film cartridge 6 existing above the camera housing 5. Good. Furthermore, the structure in which the insulating rubber base material supports and floats the conductive connecting element is not limited to the dome shape, and the conductive connecting element may be slightly formed by the insulating rubber base material having the same thickness as shown in FIG. 3A. The structure may be floated and supported, or an insulating rubber base material may be provided with a right-angled step as shown in FIG. 3B.

The hard resin for molding the conductive connector that constitutes the DX contact member of the present invention is a thermosetting resin that is easily injection-molded or press-molded, or a thermoplastic resin that is easily filled with a conductivity-imparting agent such as carbon black. Although it is preferable to select one from the group consisting of silicone rubber as an insulating rubber base material, which has an unsaturated bond functional group in the side chain, it is preferable that it has an organic bond. It is preferable to select from 1,2-polybutadiene, 1,4-hexadiene-based eletin-propylene terpolymer, epichlorohydrin-allyl glycidyl ether copolymer, diallyl phthalate resin and the like which can be oxide-crosslinked. In addition, this hard resin is supposed to have a D-type durometer hardness of 40 degrees or more, but this is a conductive material whose volume resistivity is about 10 ° to 10 ² Ω · cm by adding carbon black or the like. It is supposed to be.

The hard resin may be a hard elastomer as long as it has a D-type durometer hardness of 40 degrees or more, and examples thereof include polyester-based or polyurethane-based thermoplastic elastomers.

Here, the reason for limiting to a hard resin having a D-type durometer hardness of 40 degrees or more will be described. A for durometer hardness tester
There are two types, type D and type D, both of which are spring type hardness testers that apply a load with a push needle. A type durometer is a conical push needle with a tip of 0.79 mm in diameter and a flat angle of 35 degrees The maximum load of 822gf is applied and used for soft resin.
The type durometer is a spherical surface with a radius of 0.1 mm and the apex angle is 30
The maximum load of 4530gf is applied with a conical push needle of degree and used for soft resin. Although a graph showing the correlation between these two types of hardness is not given, for example, the actual measurement results show that a silicone rubber with an A type hardness of 60 degrees has a D type hardness of 15 degrees and an A type hardness of 90 degrees.
The degree of hardness of polyester elastomer is D type hardness of 30 degrees. And as is the case with rubber key top type keys such as calculators, general-purpose soft resin and soft rubber easily adhere to dust and are difficult to remove.When a contact element is made with such a member, dust adheres to this surface. If this happens, it may cause a poor electrical continuity. If this contact element is a hard one such as a metal contact, even if dust adheres, it is rubbed against the connected electrode to remove the dust, which also removes the dust and the oxidative coating on the surface of the connected electrode. Therefore, in the case of a metal contact, this is called a self-cleaning effect. However, when the contact element is soft, the force of rubbing against the connected electrode is weak, so this self-cleaning effect cannot be expected. As a result of various investigations, the present inventors have conducted experiments to find that such a self-cleaning effect can be obtained when a hard resin or a hard elastomer having a contact element hardness of D type durometer hardness of 40 degrees or more is used. And completed the present invention.

A conductive connector molded from such a hard resin or a hard elastomer has a favorable feeling that dust is unlikely to adhere to it, similar to the ABS resin plastic key tops currently used in desktop electronic calculators and various keyboards. In addition to exhibiting a self-cleaning effect when it comes into contact with the chromium electrode of the Patrone, it also satisfies the resistance value when used as a DX contact.

In addition, the insulating rubber base material that constitutes the DX contact member of the present invention can be easily molded, can be operated at a low stress of several tens of gf, and can provide a molded product that is durable against repeated keystrokes. Although various synthetic rubbers may be used, it is preferable to use silicone rubber in terms of electrical characteristics, durability, and moldability. This insulating rubber base material is required to support and float the above-mentioned conductive connector, which may be formed into a dome shape as shown in FIG. 1, for example. Since it is preferable that the insulating rubber base material is integrally co-crosslinked with the hard resin or hard elastomer forming the above-mentioned conductive connector, this DX
It is preferable to perform co-crosslinking molding in the presence of an organic peracid in the contact molding die.

(Example) Next, an example of the present invention will be given. In the examples, parts are parts by weight.

Example 1,2-polybutadiene-RB-820 [product name of Nippon Synthetic Rubber Co., Ltd.] 100 parts carbon black Ketschien Black EC [product name of Lion Akzo Co., Ltd.] 15 parts and organic peroxide 2 parts of Perhexa 25B (trade name, manufactured by NOF CORPORATION) were mixed and mixed uniformly to give a volume resistivity of 10 when cured.
A conductive hard resin composition which gives a cured product having a D-type rhodometer hardness of 70 degrees in Ω · cm was prepared.

Then, this resin composition was charged into a press die together with an insulating silicone rubber GC-50 [trade name of Shin-Etsu Polymer Co., Ltd.] having an A-type durometer hardness of 50 degrees at the time of curing. By heat and pressure under the conditions of ℃ and 30 kgf / cm ² , integral co-crosslinking molding was performed to make a DX contact with a hemispherical contact point of R2.0 mm.

Next, as shown in Fig. 2, this was stored in the film mounting part of the camera, and when 24 films of HR-400 film were taken [Fuji Photo Film Co., Ltd. product name], this film had DX contacts. It can be loaded smoothly without getting caught in the camera, and functions such as the number of films displayed on the camera worked without any problems. A camera equipped with this film can be loaded at 70 ° C x 95%.
There was no particular problem when the same functional test was performed after leaving it in the RH atmosphere for 24 hours to restore it to the normal state.

(Effects of the Invention) As described above, the DX contact of the present invention is constructed by piercing the above-mentioned conductive connector into the above-mentioned insulating rubber base material and supporting it by the insulating rubber base material so that it floats. , This product is cheap because it has a simple structure and is easy to assemble, it has high reliability of electrical connection, it has a self-cleaning effect, and it is difficult for dust to adhere. Therefore, it has an industrial advantage that it is particularly useful as a DX contact for a camera.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing one embodiment of the DX contact of the present invention, FIG. 2 is a conceptual diagram when the DX contact is stored in a film mounting portion of a camera, and FIG. FIG. 4 is a vertical cross-sectional view showing the embodiment, and FIG. 4 is a vertical cross-sectional view of a DX contact made of a conventionally known metal contact. 1 ... Conductive connector, 2 ... Insulating rubber base material, 3 ... Dome, 4,13 ... Printed circuit board, 5,14 ... Camera housing, 6
...... Film Patrone, 7 ...... Chrome plated electrode, 11
...... Hemispherical metal contact element, 12 ...... Gold-plated leaf spring.

Claims (1)

[Scope of utility model registration request] 1. A D-type durometer hardness (ASTM D 2240) of 4
A conductive connector having a hard resin or hard elastomer of 0 degrees or more as a base material penetrates an insulating rubber base material,
A DEX contact member, wherein the insulating rubber base material supports and floats the conductive connector.