Lens array fabrication method, and film containing base plate and film attaching instrument employed in same

A lens array fabrication method for fabricating a lens array,

• the lens array including a lens array main unit (I) and a pressure-sensitive adhesive optical film (D),
• the lens array main unit (I) including:
• a first surface and a second surface spaced from each other in an optical axis direction (hereinafter referred to as a z-direction);
• a plurality of lens surfaces formed and aligned on the first surface along a predetermined alignment direction which is perpendicular to the z-direction (hereinafter referred to as a x-direction);
• a planar optical plane on the second surface, through which light that has passed the plurality of lens surfaces is to pass, the planar optical plane defining a predetermined central area of the second surface that encompasses an entire projected region, the projected region being formed on the second surface when the lens surfaces are projected from the z-direction on the second surface, a surrounding area being defined on the second surface around the predetermined central area, the optical plane being defined by a recess that is concave relative to the surrounding area and depressed toward the lens surfaces, the optical plane extending in a direction perpendicular to the z-direction;
• and
• a pair of first guide holes or guide pins that are disposed on opposite sides over the optical plane in the x-direction on the surrounding area of the second surface, the pair of first guide holes or guide pins extending parallel to the z-direction, an adhesion area (i) being defined, which contains part of the projected region for at least part of the plurality of lens surfaces, on the optical plane of the lens array main unit (i), the pressure-sensitive adhesive optical film (D) being attached on the adhesion area (i) by an adhesive force of the pressure-sensitive adhesive optical film itself,
• the lens array fabrication method comprising:
• preparing a film-containing base plate (II) that contains the pressure-sensitive adhesive optical film (D), the film-containing base plate (II) having a base plate main element (A), the base plate main element (A) having a placement area (ii) on a first face of the base plate main element (A) in a z″-direction that corresponds to the z-direction, the placement area (ii) corresponding to the adhesion area (i), with a bonding layer (B), a non-adhesive first detachment film (C), the pressure-sensitive adhesive optical film (D), a non-adhesive second detachment film (E), and an adhesion layer (F) being stacked on the placement area (ii) in this order from the placement area (ii), a first peel strength f(C)-(D) between the first detachment film (C) and the pressure-sensitive adhesive optical film (D) being smaller than a second peel strength f(D)-(E) between the pressure-sensitive adhesive optical film (D) and the second detachment film (E), a pair of second guide holes or guide pins, which correspond to the pair of first guide holes/guide pins respectively, being provided in a region outside the placement area (ii) on the first face of the base plate main element (A), the second guide holes or guide pins being disposed on opposite sides over the placement area (ii) in a x″-direction, which corresponds to the x-direction, and the second guide holes or guide pins being parallel to the z″-direction;
• and
• preparing a film attaching jig (III) for attaching the pressure-sensitive adhesive optical film (D) onto the adhesion area (i), the film attaching jig (III) having a main body, the main body having a first end face in a z′-direction which corresponds to the z-direction, the first end face of the jig main body being an end face to be directed to the film-containing base plate (II) and the lens array main unit (I), the jig (III) having a film holding projection that is provided on the first end face of the jig, the film holding projection protruding in parallel to the z′-direction toward the film-containing base plate (II) and the lens array main unit (I), the film holding projection having a holding area (iii) at its front end face, and the holding area (iii) corresponds to the adhesion area (i) and the placement area (ii), the holding area (iii) being configured to be able to temporarily hold the pressure-sensitive adhesive optical film (D) when the film holding projection work together with the film-containing base plate (II) and the lens array main unit (I), the jig (III) also having a pair of pins or holes disposed on the first end face of the jig main body in parallel to the z′-direction, the pair of pins or holes being provided at opposite positions over the film holding projection in a x′-direction which corresponds to the x-direction, the pair of pins or holes of the jig (III) corresponding to the pair of first guide holes/guide pins respectively and also corresponding to the pair of second guide holes/guide pins respectively,
• positions and dimensions of the placement area (ii), the film holding projection, the optical plane and the lens surfaces in the lens array main unit (I), the film-containing base plate (II) and the film attaching jig (III) being decided, with the center points of the first guide holes/guide pins, the second guide holes/guide pins and the pins/holes being the references, such that the holding area (iii) which corresponds to the placement area (ii) in position and dimension can be formed on the front end face of the film holding projection, the adhesion area (i) which corresponds to the holding area (iii) in position and dimension can be formed on the optical plane, and the film holding projection can be received in the recess of the second surface,
• the foregoing being the prerequisite, the lens array fabrication method comprising:
• a first step of causing the pair of pins/holes of the film attaching jig (III) to be received in the pair of second guide holes/guide pins of the film-containing base plate (II) while the front end face of the film holding projection of the film attaching jig (III) is exposed to the stacked elements (B) to (F) on the placement area (ii) of the film-containing base plate (II), and attaching the holding area (iii) of the film holding projection onto an upper face of the adhesive layer (F), which is an uppermost layer, by an adhesive force of the adhesive layer (F);
• a second step, carried out subsequent to the first step, of removing the pair of pins/holes from the pair of second guide holes/guide pins, and causing detachment between the first detachment film (C) and the pressure-sensitive adhesive optical film (D) by taking advantage of magnitude relation between the first peel strength f(C)-(D) and the second peel strength f(D)-(E), such that the upper three layers (D) to (F) are held on the holding area (iii) of the film holding projection and separated from the lower two layers (B) and (C) which remain on the base plate main element (A);
• a third step, carried out subsequent to the second step, of causing the pair of pins/holes to be received in the pair of first guide holes/guide pins of the lens array main unit (I) while the three layers (D) to (F) held on the holding area (iii) of the film holding projection are exposed to the optical plane of the lens array main unit (I), inserting the film holding projection into the recess of the second surface together with the three layers (D) to (F), and attaching a lower face of the pressure-sensitive adhesive optical film (D), which is a lowermost layer among the three layers (D) to (F), to the adhesive area (i) on the optical plane by the adhesive force of the pressure-sensitive adhesive optical film (D);
• and
• a fourth step, carried out subsequent to the third step, of removing the pair of pins/holes from the pair of first guide holes/guide pins, and causing detachment between the pressure-sensitive adhesive optical film (D) and the second detachment film (E) such that the upper two layers (E) and (F) are held on the holding area (iii) of the film holding projection and separated from the pressure-sensitive adhesive optical film (D) which remains on the adhesive area (i),
• whereby the lens array fabrication method provides the lens array, with the pressure-sensitive adhesive optical film (D) being attached onto the adhesive area (i) and with the pressure-sensitive adhesive optical film (D) being received in the recess that is depressed from the surrounding region of the second surface toward the lens surfaces.