JPH03192301A - Substrate for light transmission body array - Google Patents

Abstract

PURPOSE:To obtain the substrate for a light transmission body array having excellent workability and good heat resistance by providing grooves for carrying light transmission bodies on a surface of a rectangular plate body made of a resin compsn. consisting of a thermoplastic resin and light shieldable particles. CONSTITUTION:The resin compsn. formed by adding a flame-retardant at need to the thermoplastic resin and the light shieldable particles is worked into an array substrate by an injection molding method, extrusion molding method, etc. The thermoplastic resin is not deformed in spite of heating to 80 deg.C and has fire retardance. Polyamide, polyester, polycarbonate, ABS, alpha-methylated styrene/AN copolymer, AAS, AES, polymethyl methacrylate, etc., are used for this resin. A carbon black, iron oxide powder, blackened resin powder, etc., are usable for the light shieldable particles. The grooves for disposing the light transmission bodies are formed on this array substrate in order to dispose the light transmission bodies thereon. The array shape is formed by arranging 240 pieces of distributed index circular cylindrical lenses between two sheets of such substrates and crimping the lenses in the state of coating the substrates with a two-pack mixing type epoxy adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a substrate for an optical transmitter array, and particularly to a substrate for an optical transmitter array using a thermoplastic resin with excellent workability.

[Prior Art] Optical transmitters, especially optical transmitter arrays consisting of optical fibers and gradient index rod-shaped lenses, have been widely used in the field of optical communications, as well as sensors for copiers, electronic blackboards, and facsimile machines in recent years. Its uses are expanding. Among the optical transmission body arrays used for these applications, arrays of gradient index rod-shaped lenses are particularly useful as sensors for image transmission devices, but the gradient index optical transmission bodies that have been used in the past are Since it is made by processing inorganic glass using an ion exchange method, it is not only expensive to manufacture, but also has the disadvantage of being brittle, and it is extremely difficult to process into optical transmitter arrays, making it expensive. This has become a bottleneck for expansion.

[Problem to be solved by the invention] In recent years, instead of inorganic glass-based gradient index rod lenses, development of plastic gradient index rod lenses has been progressing, and their workability is relatively high. The advantage of being able to produce it at low cost has attracted attention, and the development of its applications is rapidly expanding.

Conventionally, the substrates for optical transmitter arrays that have been developed are made of glass fiber-reinforced resin because these arrays are used in an atmosphere where heat of 60°C or higher is applied, and it is necessary to suppress thermal expansion in the longitudinal direction of the array as much as possible. They are made of carbon fiber-reinforced resin and have the disadvantage that cutting to align the conjugate lengths of the arrays is extremely difficult.

[Means to Solve the Problem 1] Therefore, the inventors of the present invention conducted intensive studies to obtain a substrate for an optical transmitter array with excellent workability and good heat resistance, and as a result, they decided to use a thermoplastic resin and a light shielding material as the substrate material. The present invention was completed based on the discovery that the object could be achieved by using the same method.

The gist of the present invention is to provide a rectangular plate-like body made from a resin composition comprising a thermoplastic resin and light-shielding particles, and a rectangular plate-like body provided with a groove for supporting a light transmitting body on its negative side. This is a characteristic feature of a substrate for an optical transmitter array.

The thermoplastic resin used in carrying out the present invention is one that does not deform even when heated to 80°C and is flame retardant, such as polyamide, polyester, polycarbonate, ABS, α-methylated styrene/AN Copolymer, ^^S1^ES.

Specific examples include polymethyl methacrylate, but the moldability and shape retention when the substrate is molded by extrusion molding, and the ability to form grooves for holding the optical transmitter into the molded body by extrusion molding. , considering bondability to the optical transmitter array with adhesive and machinability for setting the conjugate length of the array assembly, especially ^BS, ^AS,
Preferably, it is a thermoplastic resin selected from AES.

Further, since the substrate of the present invention is sometimes used in a hot atmosphere of 60° C. or higher, it may be necessary to make it flame retardant. Examples of the flame retardant include aluminum hydroxide, magnesium hydroxide, antimony trioxide, antimony pentoxide, inorganic flame retardants such as phosphorus compounds, halogenated polystyrene, halogenated polycarbonate I/oligomer halogenated epoxy, polyvinyl chloride, It is possible to use organic flame retardants such as halogenated polyethylene alone or in combination.

Further, as the light blocking material, carbon black, iron oxide powder, blackened resin powder, etc. can be used, but it is preferable to use a light blocking material that is as light as possible.

To make the optical transmitter array substrate of the present invention, a resin composition containing the above-mentioned resin, a light shielding material, and, if necessary, a flame retardant added thereto, can be processed into an array substrate by injection molding, extrusion molding, or the like. It is very effective to form a groove for arranging an optical transmitter in order to arrange the optical transmitter on the array substrate. Since the array substrate of the present invention is made of thermoplastic resin, it is possible to easily process the groove for arranging the optical transmission body. The groove for arranging the optical transmission body is hemispherical, U-shaped, V-shaped, or the like.

A grooved mold is preferably used to form this substrate by injection molding. Since the precision of the groove pitch of the substrate is determined by the precision of the mold, a substrate with a high precision of the groove pitch of the substrate can be easily obtained by using a highly accurate mold. However, this injection molding method has the problem that extra resin is required to fill the runner portion, leading to an increase in cost.

On the other hand, in the extrusion molding method, grooves can be formed using a nip roll using a roll in which one roll has a large number of hemispherical columns or V-shaped columns. This method can minimize the use of excess resin and has cost advantages. Moreover, continuous production is possible.

The array substrate of the present invention is made of thermoplastic resin,
In particular, when used as a short optical transmitter array substrate for facsimiles, copying machines, etc., the array can be used without causing any of the transmitted images due to elongation or warping of the array.

Especially when it is incorporated into an image sensor unit and integrated with other parts, no problems arise.

The present invention will be explained in more detail with reference to Examples below.

Example 1 An injection molding machine with a length of 228 mm, a width of 12 mm, and a thickness of 0.7
Attach a mold with 240 semi-cylindrical convex parts with a radius of curvature of 0.475 mm at a pitch of 0.95 mm on the surface using a tram, and set the screw temperature at 250°C and the mold temperature at 50°C.
After setting the cycle time to 60 seconds, BS resin was added to the black color to obtain a substrate.

Take the runner part from the obtained molded substrate and measure it to a length of 22 mm.
8m, width 12mm, thickness 0.7mm, groove pitch 0.95mm
A substrate with a groove depth of 0.3 mm was obtained.

Between these two substrates, 240 gradient index cylindrical lenses with a diameter of 920-1, a refractive index distribution constant g value of 0.54 mm, a center refractive index of 1.515, and a lens length of 20 mm are arranged,
Clamp with a two-component mixed epoxy adhesive applied,
An array shape was formed. This array was pressed from the substrate side (2 kgf/cffl) and left at 60''C for 10 minutes.Then, the protruding surface of the lens of this array was cut to obtain an array with a lens length of 7.0m. to dipentaerythritol, 20 parts by weight of hexaacrylate, trimethylolpropane triacrylate, 2
- Immersion in a photopolymerizable composition consisting of 60 parts by weight of propatool, 3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and 1 part by weight of a photopolymerization initiator, and then volatilizing the 2-propatool; - Photocured with a chemical lamp to form a smooth surface. This lens array had a lens length of 7.0 mm and a conjugate length of 14.4 mm.

Also, the resolution (MTF) is 0° at a spatial frequency of 41P/m.
There was no change in resolution depending on the operating temperature: 61% at C, 63% at 25°C, and 62% at 60''C.

Furthermore, no problems were caused by thermal expansion or the like. As a result of incorporating this into an actual image sensor unit,
It could be used satisfactorily for image transmission.

Example 2 Black ABS resin barrel part 220°C1 die part 190
Single screw extruder heated to ``C'' (barrel 30mmφX800
m, dice slit 10 times x 1), 90 per minute
A sheet-like material having a width of 11 mm and a thickness of 0.9 m was continuously obtained at a speed of 0 mm. This sheet-like material has a semi-cylindrical convex portion of 0.9
It was sandwiched between a metal heating roll with a diameter of 100 mm and a metal flat roll with a diameter of 100 mm, which had a pitch of 5 m on the surface, and was continuously transferred at a speed of 1,000 mm per minute.
A grooved sheet having a diameter of 0.6 mm and a thickness of 0.6 am was obtained, and this sheet was continuously cut at intervals of 3.4 seconds to obtain an array substrate.

The shape of the board is 296 mm long, 11.5 mm wide, and 0.6 mm thick.
The plate had a groove pitch of 0.96 mm and a groove depth of 0.19 mm. Using this substrate and using the same lenses as in Example 1, a lens array was obtained in the same manner as in Example 1. In this lens array, the resolution is slightly worse than the lens array of Example 1 because the groove pitch fluctuates due to extrusion molding <1! P/
The spatial frequency resolution (MTF) of the cabinet is 58 at 25°C.
%, 57% at 0°C and 57% at 60°C, and there was no change in resolution depending on the operating temperature. As a result of incorporating this into an actual image sensor unit, it was able to be used satisfactorily for image transmission.

Example 3 A substrate was obtained by injection molding using the same mold as in Example 1 using black acrylic resin. The substrate had a length of 301 mm, a width of 12 mm, a thickness of 0.7 mm, a groove pitch of 0.95 m, and a groove depth of 0.3 mm. Using this substrate and using the same lenses as in Example 1, a lens array was obtained in the same manner as in Example 1. This lens array has a conjugate length of 1
At 4.4 Peng, the resolution (MTF) is 62% at 0°C, 64% at 25°C, and 70°C at a spatial frequency of 41P/IIIl.
The resolution was 63%, and there was no change in resolution depending on the operating temperature. ,
As a result of incorporating this into an actual image sensor unit, it was possible to use it for image transmission.

Comparative Example 1 A substrate was obtained by injection molding using the same mold as in Example 1 using glass fiber reinforced ABS. The shape of the substrate was 301 m long, 12 mm wide, 0.7 m thick, groove pitch 0.95 m, and groove depth 0.3 m. Using this substrate and using the same lenses as in Example 1, a lens array was created in the same manner as in Example 1.

At that time, a problem arose in that the cutting blades were worn out very quickly in the process of cutting into an array with a lens length of 7.0 m.

Claims (1)

[Claims] 1. A substrate for an optical transmitter array, characterized in that it is a rectangular plate made of a resin composition of a thermoplastic resin and light-blocking particles, and has grooves for holding the optical transmitter provided on one side thereof.