JP2742867B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image device such as an LED head, an EL head, and an image sensor, and more particularly to a monocular lens array used.

[0002]

2. Description of the Related Art The use of an array of monocular lenses in an imaging device has long been known. However, precise mounting accuracy is required for a monocular lens, and for example, mounting accuracy with an error of ± 10 μm or less, preferably ± 5 μm or less is required. It is extremely difficult to mount a monocular lens accurately in this way, and if the mounting accuracy is insufficient, white streaks or black streaks occur at the joint between images between the lenses. This is because, for example, when a light emitting array is used, the dot interval changes at the transition between lenses, and when dots overlap, black streaks are formed, and when dots are separated, white streaks are formed. This is the same when using the light receiving array. In order to improve the mounting accuracy of the monocular lens, it has been proposed to accurately provide a groove in the lens holder and accommodate and position the lens in the groove, but it is extremely difficult to accurately position and provide the groove. For example, it is practically impossible to accurately cut out grooves by machining, and even when grooves are formed by molding, the accuracy of the mold and the actual molded product does not match the mold and the actual molded product Extremely difficult because there are differences.

[0003] If the coefficient of thermal expansion differs between the monocular lens array side and the light receiving / emitting array side, misalignment occurs due to a change in temperature, and white streaks and black streaks occur. On the other hand, it has been proposed to insert-mold a monocular lens into a holder, but this is extremely expensive.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to 1) enable a monocular lens to be accurately mounted on a base plate and improve image quality. Another object of the present invention is to prevent the mounting accuracy from being lowered by an adhesive used for fixing the lens. A third object of the present invention is to provide, in addition to 1), 3) making the thermal expansion coefficients of the monocular lens side and the light receiving / emitting array side uniform so as to prevent white streaks and black streaks due to temperature changes.

[0005]

According to the present invention, in an image apparatus using a monocular lens array and a light receiving / emitting array, the monocular lens array is provided on a first main surface of a transparent substrate with a positioning marker and a flat plate side reference surface. A base plate provided with
The monocular lens is mounted on the base plate, and the monocular lens is provided with an edge having a flat bottom surface around the lens, the bottom surface being the first reference surface of the lens, and the side surface of the edge being the second reference surface of the lens. The first reference surface of the lens is brought into contact with the reference surface on the plate side, and the second reference surface of the lens is positioned by a positioning marker on the base plate.
Preferably, a groove is provided in the first main surface of the substrate to accommodate an adhesive, and a part of the bottom surface of the edge of the monocular lens is fixed with the adhesive. Preferably, the light receiving and emitting array is mounted on the second base plate, and the coefficient of thermal expansion between the base plate of the monocular lens array and the second base plate is made substantially equal. As the light receiving / emitting array, an EL array, a CCD array, or the like is used in addition to the LED array shown in the embodiment.

[0006]

According to the present invention, the first lens provided on the bottom surface of the edge of the monocular lens on the plate side reference surface of the base plate.
The reference surface is brought into contact, and the lens second reference surface provided on the side surface of the edge of the monocular lens is positioned by the marker on the base plate. As a result, the height of the monocular lens viewed from the base plate is positioned with respect to the plate-side reference plane and the lens first reference plane,
The horizontal position of the monocular lens is positioned by the second reference plane of the lens and the marker, and the height and the horizontal position of the monocular lens are accurately determined. What is necessary for this is to provide a flat plate-side reference surface and a marker on the base plate, and to provide the first and second reference surfaces of the bottom surface and side surfaces of the edge of the monocular lens to easily position the monocular lens. Can be.

According to the second aspect of the present invention, an adhesive is accommodated in a groove provided in the base plate, and the bottom surface of the edge of the monocular lens is fixed to the base plate with the adhesive. In this way, the adhesive does not overflow from the groove, and the adhesive spreads between the bottom surface of the edge and the main surface of the base plate in a portion other than the groove,
The height of the monocular lens with respect to the base plate does not vary by the thickness of the adhesive. In the invention of claim 3,
The coefficients of thermal expansion of the base plate of the monocular lens and the second base plate on the light receiving / emitting array side are made substantially equal. Since the monocular lens and the light receiving / emitting array are fixed to each base plate, even if their thermal expansion coefficients differ, the actual thermal expansion is determined by the thermal expansion of the base plate, and the thermal expansion coefficients of the two base plates are almost the same. By doing so, it is possible to make the thermal expansion of the light receiving and emitting array and the monocular lens the same, and to prevent white streaks and black streaks due to temperature changes.

[0008]

1 to 3 show a monocular lens array after assembly. In these figures, reference numeral 2 denotes a transparent base plate made of plastic, glass, or the like. Base plate 2
The first main surface 4 is provided with a substantially U-shaped marker 6 and a groove 8, and a part of the groove 8 accommodates the adhesive 10. Reference numeral 12 denotes a monocular lens using a lens such as glass or plastic,
As shown in FIG. 4, an edge 16 is provided around the lens portion 14, and the bottom surface of the edge 16 is flattened to form a lens first reference surface 18. In addition, four side surfaces of the edge 16 are exposed and used as a lens second reference surface 20. The lens unit 1 is also provided on the opposite side of the lens unit 14.
5 are provided, and one convex lens is formed by the lens portions 14 and 15.

FIG. 5 shows the base plate 2 before the monocular lens 12 is mounted. The concave portion 22 for receiving the lens portion 15 is provided, and the concave portion 22 is slightly larger than the lens portion 15 so that play occurs between the two. To The first main surface 4 of the base plate 2 is flat except for the markers 6, the grooves 8, and the recesses 22. Of these, the area that is in contact with the lens first reference surface 18 surrounded by the markers 6, 6 is referred to as the plate-side reference. Surface 24. The recess 22 and the groove 8 are
It can be easily provided by using a plastic and molding. Then, at the time of molding, the first main surface 4 excluding the concave portion 22 and the groove 8 becomes flat. After the molding, the marker 6 is obtained by vacuum-depositing Al, Cr, or the like on the entire surface of the first main surface 4 using the concave portion 22 and the groove 8 as a mask and etching using another mask. The accuracy of the marker 6 is determined by the accuracy of the mask, and the mounting accuracy of the monocular lens 12 is determined by the accuracy of the marker 6.
Is determined by the precision of

Returning to FIGS. 2 and 3, the first lens reference surface 18 of the monocular lens 12 is positioned in contact with the plate-side reference surface 24, and the second lens reference surface 20 is positioned by the marker 6. To be precise, two ends of the lens second reference surface 20 on the right side of the monocular lens 12 (the two ends perpendicular to the first main surface 4).
Two edges) are positioned at the two vertices inside the marker 6. As a result, the height of the monocular lens 12 with respect to the base plate 2 is determined by bringing the lens first reference surface 18 into contact with the plate-side reference surface 24, and the position of the monocular lens 12 on the first main surface 4 is determined by the lens By positioning the second reference surface 20 with respect to the marker 6, the base plate 2 is positioned in both the long side direction and the short side direction. In the embodiment, the pair of markers 6 and 6 are provided on both sides of the monocular lens 12, but only the right marker 6 is used for positioning, and the left marker 6 is for confirming that the positioning is correct. In the monocular lens 12, all four side surfaces of the edge 16 are used as the lens second reference surfaces 20. However, only one surface is actually used, and which of the four side surfaces of the edge 16 is positioned with respect to the marker 6. If it is determined that the operation is to be performed, only that surface may be exposed and used as the lens second reference surface 20. The lens first reference surface 18 is partially fixed to the base plate 2 by the adhesive 10. Here adhesive 10
Is accommodated in the groove 8, the adhesive 10 overflows and spreads, enters between the lens first reference surface 18 and the plate-side reference surface 24, and the distance between the two reference surfaces 18, 24 fluctuates. There is no. As a result, the monocular lens 12 is also moved in the height direction with respect to the base plate 2 in the first main surface 4.
, And are mounted precisely at the same pitch.

FIG. 6 shows a modified example of the base plate 3. In this modification, a marker 28 is provided on the entire surface of the first main surface other than the portion in contact with the monocular lens 12, and this is used as a black mask to block light. For example, a vapor deposited film of Cr or the like is used as the marker 28 to absorb or scatter unnecessary light so that light does not leak from portions other than the monocular lens 12. In this case, the lens second reference plane 20 of the monocular lens 12 is positioned using the four vertices 29 inside the marker 28. The other points are the same as those of the base plate 2 in FIG.

FIG. 7 shows the mounting of the monocular lens 12 on the base plate 2. The monocular lens 12 is conveyed by a collet 40, and the marker 6 and the lens second reference plane 20 are monitored by a television camera 42 or the like and displayed on a monitor 44. In the image processing device 46, the upper and lower two in the figure of the lens second reference surface 20 are shown.
One vertex and two vertices inside the marker 6,
By calculating these distances, the moving distance of the collet 40 is determined. Next, the collet 40 is lowered, and the monocular lens 12 is mounted, and fixed with the adhesive 10. At this time, the first lens reference surface 18 contacts the flat plate-side reference surface 24, and the second lens reference surface 20 is positioned by the marker 6. In the embodiment, the marker 6 is formed into a U-shape, and the monocular lens 12 is formed.
Are positioned both in the long side direction and the short side direction of the first main surface 4. However, the marker 6 may be simply linear and positioned only in the long side direction of the first main surface 4.

FIG. 8 shows a main part of the image apparatus. In the figure, reference numeral 30 denotes a second base plate having a coefficient of thermal expansion substantially equal to that of the base plate 2, for example, it is preferable that the difference between the two coefficients of linear thermal expansion be within a range of ± 5 × 10 ⁻⁷ / ° C. or less. . For example, when a transparent plastic is used for the base plate 2, a plastic plate such as glass epoxy is used for the second base plate 30, and the difference in linear thermal expansion coefficient is within the above range. 32 is an LED array mounted in a row on the second base plate 30, 34 is a spacer at the center, 36 and 36 are spacers at both ends,
38 is an elastic adhesive. The center spacer 3
Reference numeral 4 denotes an adhesive such as epoxy, which is fixed so that the distance between the base plates 2 and 30 does not change. The reason that the spacers 36 at both ends are fixed with the elastic adhesive 38 in order to free the ends of the base plates 2 and 30 from deformation and prevent deformation of the base plates 2 and 30 in the focal direction can be prevented. The effect is obtained. The spacer 34 at the center is used to make the interval between the base plates 2 and 30 constant, and the interval between them may be made constant by using a screw or the like instead of the spacer 34.

[0014]

According to the first aspect of the present invention, 1) the monocular lens is accurately mounted on the base plate to prevent the generation of white streaks and black streaks due to the displacement of the monocular lens, thereby improving image quality. In addition, in the invention of claim 2, in addition to this, 2) the adhesive used for fixing the lens is the plate side reference surface and the first lens.
It is prevented from getting into the gap between the base plate and the reference surface, so that the mounting accuracy in the height direction with respect to the base plate is prevented from being reduced by the adhesive. According to the invention of claim 3, in addition to 1), 3)
The thermal expansion coefficients of the monocular lens side and the light emitting / receiving array side are made uniform, and the occurrence of white streaks and black streaks due to temperature changes can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a monocular lens array according to an embodiment.

FIG. 2 is a sectional view of a main part of the monocular lens array according to the embodiment.

FIG. 3 is a cross-sectional view in a short half direction of the monocular lens array according to the embodiment.

FIG. 4 is a side view of the monocular lens of the embodiment.

FIG. 5 is a plan view of a main part of a monocular lens-side base plate according to the embodiment.

FIG. 6 is a plan view of a main part of a monocular lens-side base plate according to a modified example.

FIG. 7 is a diagram showing a process of assembling a monocular lens array.

FIG. 8 is a side view of a main part of the image device.

[Explanation of symbols]

 2, 3 base plate 4 first main surface 6, 28 marker 8 groove 10 adhesive 12 monocular lens 14, 15 lens portion 16 edge 18 lens first reference surface 20 lens second reference surface 22 concave portion 24, 26 plate side reference surface 30 Second base plate 32 LED array 34, 36 Spacer 38 Elastic adhesive 40 Collet 42 TV camera 44 Monitor 46 Image processing device

Claims (3)

(57) [Claims] 1. An image apparatus using a monocular lens array and a light receiving / emitting array, wherein the monocular lens array is provided with a positioning marker and a flat plate-side reference surface on a first main surface of a transparent substrate. A base plate and an individual monocular lens mounted on the base plate, wherein the monocular lens has a flat bottom edge around the lens, the bottom surface is a lens first reference surface, and the side surface of the edge is a lens. An image apparatus comprising: a second reference surface; a lens first reference surface in contact with a plate-side reference surface; and a lens second reference surface positioned by a positioning marker on a base plate. 2. The monocular lens according to claim 1, wherein a groove is provided in the first main surface of the substrate to accommodate an adhesive, and a part of the bottom surface of the edge of the monocular lens is fixed by the adhesive. Image device. 3. The image apparatus according to claim 1, wherein the light receiving / emitting array is mounted on the second base plate, and the base plates of the monocular lens array and the second base plate have substantially equal thermal expansion coefficients.