JP2011210305A - Resin lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin lens with which inclination of the resin lens is accurately obtained even when reflected light from a mirror surface part of the resin lens does not condense to nearly one point in measuring the inclination of the resin lens.SOLUTION: The resin lens includes an optical functional part 2 which has an optical function, and a face part 41 for measurement which is arranged on a periphery of the optical functional part 2 and which can measure inclination of an optical axis of the optical functional part based on reflection of light. Differently reflecting regions 42 are provided on the face part 41 for measurement. A light reflectance and/or a direction of light reflection of the differently reflecting regions 42 are/is set to be different from those/that of the main region 53 of the face part for measurement, which is a region of the face part 41 for measurement other than the differently reflecting regions 42. Three or more differently reflecting regions 42 are provided in the circumferential direction of the optical functional part 2 with spacings.

Description

  The present invention relates to a resin lens that is a resin lens.

In recent years, as an objective lens (pickup lens) used for an optical pickup device for reading and writing of an optical disk such as a Blu-ray disc, DVD, or CD, a lens made of a thermoplastic resin, for example, is used instead of a glass mold lens. Such an objective lens is formed by, for example, injection molding.
Resin lenses are also used in various cameras such as so-called digital cameras, camera-equipped mobile phones, and video cameras.

  The resin lens as the objective lens of the optical pickup device includes, for example, an optical function unit having an optical function such as a light collecting function, and a flange unit used for positioning and fixing to the optical device. And the flange part is formed in the hook shape on the outer periphery of the optical function part, for example.

Further, since the resin lens as the objective lens is disposed close to the optical disk, for example, the resin lens is attached to the tip portion of the attachment frame to which the objective lens of the optical pickup device is attached. At this time, for example, the optical functional portion of the resin lens is disposed on the inner peripheral side of the mounting frame, the flange portion is disposed on the frame portion of the mounting frame, and the flange portion is fixed to the mounting frame by, for example, adhesion.
Therefore, the resin lens is in a state where the side that peels off the optical disk is exposed in a state of being attached to the optical pickup device.

A mirror surface portion is provided on the flange portion that does not interfere with the optical function of the surface of the resin lens that faces the optical disk exposed as described above. The mirror surface portion is formed in a portion formed by the mirror-finished portion by performing mirror surface processing on the forming surface of the mold forming the flange portion.
This mirror surface portion is formed in an annular shape on the inner peripheral side of the flange portion, and is formed by the mirror surface processing portion of the above-described mold frame, thereby reducing the surface roughness than other portions, thereby reflecting light. It is a reflective surface that reflects light with an increased rate.

  For example, when the resin lens is attached to the optical pickup device as described above, the mirror surface portion irradiates light toward the mirror surface portion and reflects light reflected from the mirror surface portion with an optical sensor (here, for example, a CCD). For example, the inclination of the resin lens (the optical axis of the lens) can be detected from the intensity of the emitted light, the measurement position, the measured shape, and the like (for example, Patent Document 1 to Patent Document 3). See).

Patent Document 3 describes providing a reflective surface that functions in the same manner as a mirror surface portion by providing a reflective film on a planar portion of a resin lens as a conventional technique.
In addition, there has been proposed a resin lens that reflects only light of a predetermined wavelength when a reflective surface is provided on the resin lens (see, for example, Patent Document 4).

Japanese Patent Laid-Open No. 10-282392 JP 2001-134975 A JP 2008-58336 A JP 2001-34991 A

By the way, the reflected light from the mirror surface portion of the resin lens is condensed by a condensing lens or the like and irradiated to an optical sensor such as a CCD camera. Therefore, if the mirror surface portion formed in an annular shape is sufficiently flat and smooth, the reflected light from the mirror surface portion is collected at approximately one point, and the bright light collected at approximately one point by the optical sensor is collected. By detecting the position of the point, the inclination of the resin lens can be accurately grasped.
However, in an actual resin lens, the surface shape of the mirror surface portion is distorted or the surface roughness changes, so that the reflected light from the mirror surface portion diffuses and is not condensed at one point, but is condensed. The shape irradiated to the optical sensor may not be a shape close to a circle, and the light collecting shape may vary depending on the resin lens. In this case, the condensing position when the reflected light is condensed at one point cannot be determined, and the inclination of the lens (optical axis) cannot be accurately grasped.

  The present invention has been made in view of the above circumstances, and a resin lens that can improve measurement accuracy when reflected light from a mirror surface portion of a resin lens is not collected at substantially one point when measuring the tilt of the resin lens. The purpose is to provide.

In order to achieve the above object, the resin lens according to claim 1 is provided around an optical function part having an optical function, the optical function part, and based on reflection of light. And a measuring surface part capable of measuring the inclination of the optical axis of the functional part,
The measurement surface portion is provided with a different reflection region,
The different reflection area is set to have a light reflectance and / or a light reflection direction different from those of the measurement surface main body area which is an area of the measurement surface area other than the different reflection area, and the optical It is characterized in that three or more are provided at intervals in the circumferential direction of the functional part.

  In the first aspect of the present invention, for example, the measurement surface portion main body region is a surface (mirror surface portion) having high light reflectance, and the different reflection region provided on the measurement surface portion is a measurement surface portion main body region. And the reflectance is different and the light reflectance is low. In this case, when light is irradiated to the measurement surface portion, and the reflected light from the measurement surface portion is condensed and irradiated to the optical sensor, the light irradiated to the optical sensor must be condensed at approximately one point. Based on the fact that the amount of reflected light from the different reflection area of the measurement surface portion is small, three or more dark areas are generated in the shape of the reflected light irradiated to the optical sensor according to the number of the different reflection areas. . In this case, the shape of the reflected light is a shape having a bright protrusion between three or more dark regions, and the optical axis of the resin lens with the center of the three or more protrusions as the center of the reflected light. By measuring the inclination, it is possible to improve the measurement accuracy of the inclination of the optical axis of the resin lens even if the reflected light is not collected at substantially one point.

  On the other hand, even if the measurement surface section main body area is a surface with low light reflectance, and the different reflection area is different from the measurement surface section main body area, the light sensor also has a high light reflectance. The dark part and the bright part of the shape of the reflected light applied to the light are reversed, but the shape of the reflected light has a bright protrusion between three or more dark regions. By measuring the inclination of the optical axis of the resin lens with the center of the three or more protrusions as the center of the reflected light, the inclination of the optical axis of the resin lens can be reduced even if the reflected light is not condensed at one point. Measurement accuracy can be improved.

  According to a second aspect of the present invention, in the resin lens according to the first aspect, the measurement surface portion is formed in an annular shape, and the different reflection region ranges from an outer peripheral edge to an inner peripheral edge of the measurement surface portion. , A region including an inner periphery without including an outer periphery of the measurement surface portion, and a region including an outer periphery without including an inner periphery of the measurement surface portion. And

  In the invention according to claim 2, a region including a range from the outer periphery to the inner periphery of the measurement surface portion, a region including the inner periphery without including the outer periphery of the measurement surface portion, and the inner periphery of the measurement surface portion In response to characteristics such as distortion of the surface of the measurement surface portion based on the shape of the resin lens, etc., in the region including the outer periphery without including the outer peripheral edge, the different reflection region is set so that the above-described dark region becomes the most clear be able to.

  According to a third aspect of the present invention, there is provided the resin lens according to the first or second aspect of the present invention, wherein the extra-reflection area has a relatively increased reflectance or a reflectance relative to the measurement surface main body area. It is formed by suppressing.

In the invention according to claim 3, the reflectance of the different reflection region is increased or suppressed relative to the measurement surface main body region to thereby increase the reflectance of the different reflection region. It is different from the main body area. In this case, for example, in the portion where the measurement surface portion of the mold for molding the resin lens is formed, if the surface roughness of the portion that becomes the different reflection region with respect to the measurement surface portion is increased, the reflectance is suppressed. When the surface roughness is reduced, the reflectance is increased.
In addition, when the reflectance is suppressed, the reflectance can be suppressed by providing an antireflection film in a portion that becomes a different reflection region of the measurement surface portion. In addition, when the reflectance is increased, the reflectance can be increased by providing a reflective film in a portion that becomes a different reflection region of the measurement surface portion.
Also, by increasing or suppressing the reflectance of the measurement surface portion main body region, which is a portion excluding the different reflection region of the measurement surface portion, as in the case of the above-described different reflection region, the reflectance of the different reflection region is relatively increased. It can be increased or suppressed with respect to the measurement surface portion.

  The resin lens according to claim 4 is characterized in that, in the invention according to any one of claims 1 to 3, four different reflection regions are formed on the measurement surface portion. .

  In the invention according to claim 4, when the light reflected from the measurement surface portion and collected and irradiated to the optical sensor is not collected at substantially one point, the shape of the light irradiated to the optical sensor is obtained. The four dark portions are formed corresponding to the different reflection regions or the portions between the different reflection regions of the measurement surface portion where the reflectance is relatively low. Correspondingly, the shape of the light irradiated to the optical sensor is such that the above-mentioned four protrusions are formed, and a portion close to a cross is formed, and the portion where the bright portion intersects is condensed at approximately one point. By using instead of the light spot in the case, the measurement accuracy of the inclination of the optical axis of the resin lens can be improved.

  The resin lens according to claim 5 is the resin lens according to any one of claims 1 to 4, wherein the measurement surface portion is formed in an annular shape, and the measurement surface portion main body region is the different region. A reflectance is set high with respect to the reflection region, and an annular antireflection film is provided to cover a part of the measurement surface portion in the circumferential direction of the measurement surface portion.

  In the invention according to claim 5, by providing an annular antireflection film that covers a part of the annular measurement surface portion whose reflectance is higher than that of the different reflection region in the circumferential direction, When the reflected light of the measurement surface portion is not collected at substantially one point due to distortion or the like, the light is condensed on the optical sensor by covering the annular measurement surface portion in an annular shape and narrowing the width along the radial direction. It is possible to reduce the shape of the reflected light and improve the accuracy in measuring the tilt of the resin lens.

  The resin lens according to claim 6 is the invention according to any one of claims 1 to 5, wherein the measurement surface portion is formed on a slope that is recessed from the outer peripheral side toward the inner peripheral side. It is characterized by that.

  In the invention according to claim 6, the light reflected from the measurement surface portion can be reliably irradiated to the optical sensor by forming the measurement surface portion as an inclined surface that is recessed from the outer peripheral side toward the inner peripheral side. Thereby, the measuring system of the inclination of the optical axis of a resin lens can be improved.

  According to the present invention, with respect to the occurrence of the distortion of the condensing shape of the reflected light from the mirror surface due to the distortion of the surface of the conventional mirror surface or the roughness of the surface, the distortion of the surface described above is applied to the different reflection region. By deliberately providing a deviation in the reflection direction or a difference in reflectance that is greater than the fluctuation in surface roughness, the shape of the light collection is positively changed, and the portion of the light collection shape clearly changed due to the different reflection region On the basis of this, the measurement accuracy can be improved by narrowing a range that is a reference for measurement of the condensing shape.

It is a figure which shows the resin lens which concerns on 1st Embodiment of this invention, Comprising: (a) is a side view used as the 1st surface side, (b) is sectional drawing, (c) is the 2nd surface side FIG. It is a side view of the 1st surface side which shows the resin lens which concerns on 2nd Embodiment of this invention. It is a 1st surface side view which shows the resin lens which concerns on 3rd Embodiment of this invention. It is a 1st surface side view which shows the resin lens which concerns on 4th Embodiment of this invention. It is a 1st surface side view which shows the resin lens which concerns on 5th Embodiment of this invention. It is a figure which shows the resin lens of 5th Embodiment, Comprising: (a) is sectional drawing, (b) is a principal part enlarged view of (a). It is a figure which shows the resin lens of 6th Embodiment of this invention, Comprising: (a) is sectional drawing, (b) is a principal part enlarged view of (a). It is a 1st surface side view which shows the resin lens which concerns on 7th Embodiment of this invention. It is a 1st surface side view which shows the resin lens which concerns on 8th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1A, 1B, and 1C, the resin lens 1 of the first embodiment is used as a pickup lens (objective lens) of an optical pickup device such as a CD, a DVD, or a Blu-ray disc. Is.
Here, in the description of the shape of the resin lens 1, a predetermined reference surface that is orthogonal to the optical axis and is within the thickness is along the parting line between the fixed mold and the movable mold in this example. The distance along the optical axis direction from the reference plane is expressed as height. In addition, it is so high that it leaves | separates from a reference plane, and becomes low, so that it approaches. In addition, the distance from the reference plane is expressed by the height on both the first surface 11 side and the second surface 12 side, which will be described later.

A resin lens 1 as a pickup lens includes an optical function part 2 having an optical function such as a light collecting function, and a flange part 3 formed in a bowl shape around the optical function part 2.
The resin lens 1 has a second surface 12 facing the optical disc side where information is read and written, and a first surface 11 on which light from the light source is incident, each of which is a surface of the optical function unit 2. Optical function surfaces 21 and 22 to be and flange surfaces 31 and 32 to be surfaces of the flange portion 3.
That is, the first surface 11 has an optical functional surface 21 at the center and a flange surface 31 at the outer periphery. The second surface 12 has an optical functional surface 22 at the center and a flange surface 32 at the outer periphery.

On the first surface 11 side of the resin lens 1, the optical functional surface 21 of the optical functional unit 2 is curved and protrudes toward the light source side (opposite side of the optical disk).
The optical function surface 21 on the second surface 12 side of the optical function unit 2 is disposed close to the optical disk, and has a shape that is gently curved. At least a part of the flange surface 32 on the second surface 12 side of the flange portion 3 is higher than the optical function surface 21 on the same second surface 12 side, and the flange portion 3 is more than the optical function portion 2. It is in a state of protruding to the optical disc side.

  The resin lens 1 is attached to the optical pickup device. The attachment position of the resin lens 1 is the position closest to the optical disk in the optical pickup device, and the resin lens 1 is attached to the attachment frame at the tip of the optical pickup device. The flange portion 3 is fixed. At this time, the reference surface 33 of the flange surface 31 on the first surface 11 side of the resin lens 1 is brought into contact with the front end surface of the mounting frame and is, for example, bonded and fixed. And the optical function part 2 respond | corresponds to the internal space of an attachment frame, and light can pass through.

On the second surface 12 of the resin lens 1 facing the optical disk side, the flange surface 32 of the flange portion 3 is composed of an inner peripheral portion 34 on the inner peripheral side and an outer peripheral portion 35 on the outer peripheral side. 41 is provided.
The measurement surface portion 41 is formed on the flange surface 32 of the flange portion 3 on the second surface 12 side of the resin lens 1. The measurement surface portion 41 is formed in an annular band shape continuously to the outer peripheral edge of the optical function surface 22 on the second surface 12 side of the optical function portion 2 formed in a circular cross section of the resin lens 1. . That is, the measurement surface portion 41 is formed as a surface continuous with the optical functional surface 22 on the inner peripheral portion 34 continuous with the optical functional surface 22 of the flange surface 32.
The measurement surface portion 41 is a plane orthogonal to the optical axis of the optical function portion 2 within an allowable error range.

  Such a measurement surface portion 41 faces the optical disc side when the resin lens 1 is attached to the attachment frame. When the resin lens 1 is installed and fixed to the mounting frame of the optical pickup device, the measurement surface portion 41 is irradiated with light, and the reflected light from the measurement surface portion 41 is condensed and irradiated onto a predetermined optical sensor. Thus, the inclination of the resin lens 1 on the mounting frame (the inclination of the optical axis of the resin lens 1) can be measured.

For example, the inclination of the resin lens 1 (its optical axis) is measured based on the amount of deviation from the reference position of the position of the reflected light from the measurement surface 41 measured by the optical sensor.
Details of the measurement surface portion 41 will be described later.
Further, on the second surface 12, an outer peripheral portion 35 higher than the measurement surface portion 41 of the inner peripheral portion 34 and the optical functional surface 22 on the inner peripheral side thereof is formed outside the inner peripheral portion 34 of the flange portion 3. ing. Since the outer peripheral portion 35 protrudes higher than the measurement surface portion 41 and the optical functional surface 22, the outer peripheral portion 35 protects the measurement surface portion 41 and the optical functional surface 21 on the inner peripheral side.

The resin lens 1 is formed by injection molding, and uses an injection mold having a movable mold and a fixed mold, and one of the first surface 11 and the second surface 12 of the resin lens 1 is used. The surface side is molded by a movable mold, and the other surface is molded by a fixed mold.
Moreover, the part including the optical function part 2 of the resin lens 1 and the inner peripheral side part of the flange part 3 is shape | molded by the nests 71 and 72 provided in the movable mold and the fixed mold, respectively.
On the first surface 11 of the resin lens 1, the reference surface 33 and the optical function surface 21 on the inner peripheral side thereof are molded with the formation surface formed on the insert 71, and on the second surface 12 of the resin lens 2, the measurement surface portion 41. The optical function surface 22 on the inner peripheral side is formed by the insert 72. Further, a gate cutting portion 50 is formed at one location on the outer peripheral edge of the resin lens 1 by cutting the gate at the time of molding.

In such a resin lens 1, the measurement surface portion 41 is provided with three or more different reflection regions 42. The measurement surface portion 41 includes a measurement surface portion main body region 43 other than the different reflection region 42 and three or more different reflection regions 42.
In the first embodiment, there are four different reflection regions 42 provided on the measurement surface portion 41. Further, the different reflection region 42 is formed from the inner peripheral edge to the outer peripheral edge of the measurement surface portion 41 in the annular and band-shaped measurement surface portion 41. Further, the different reflection regions 42 are arranged at intervals in the circumferential direction of the measurement surface portion 41, that is, in the circumferential direction of the optical function portion 2. Further, the intervals between adjacent different reflection areas 42 are substantially the same, and the different reflection areas 42 are arranged at substantially equal intervals in the circumferential direction.

In the first embodiment, the reflectance of light in the different reflection region 42 is lower than the reflectance of light in the measurement surface main body region 43. The light used for the measurement of the inclination of the resin lens is, for example, 650 nm, and in particular for the light in a wavelength range including this wavelength and wavelengths in the vicinity thereof, the measurement surface body region 43, The reflectance needs to be different between the different reflection regions 42.
In addition, when the wavelength of light used for measurement of the inclination of the resin lens is different from the above-described 650 nm, the reflectance of light in the wavelength region for measurement differs between the measurement surface main body region 43 and the different reflection region 42. It only has to be.

The difference between the light reflectance of the measurement surface portion main body region 43 and the light reflectance of the different reflection region 42 is based on a manufacturing error when the measurement surface portion main body region 43 is formed as a reflective surface having a uniform reflectance. It is preferable to be larger than the difference in reflectance depending on the position. Further, the decrease in the amount of reflected light of the measurement surface portion 41 due to the decrease in the light reflectance of the different reflection region 42 is applied to the optical sensor based on the influence of light reflection due to the distortion of the surface of the measurement surface portion 41. It is preferable that the amount of reflected light is larger than the amount of reflected light.
Further, the measurement surface portion main body region 43 increases the light reflectivity by applying mirror processing to the molding surface forming the measurement surface portion main body region 43 of the mold (nesting 72) in the same manner as the conventional mirror surface portion. Therefore, the reflectance is high. On the other hand, the different reflection area 42 is low by suppressing the reflectance of light by roughening the formation surface forming the different reflection area 42 of the mold (nest 72) and increasing the surface roughness. Yes.

Moreover, as a method of making the reflectance of light different between the measurement surface portion main body region 43 and the irregular reflection region 42, instead of processing the molding surface of the mold for molding the resin lens 1 as described above, In the post-processing after molding the resin lens 1, the measurement surface portion main body region 43 may be mirror-finished to increase the light reflectance, and the surface of the different reflection region 42 may be roughened to reduce the light reflectance. .
Further, the reflectance of light is set to a desired value by processing one of the measurement surface portion main body region 43 and the extra-reflective region 42 by processing the forming surface of the mold, and the other is processed by the post-processing described above. May be set to a desired value.

  Further, as a method of making the light reflectance different between the measurement surface main body region 43 and the different reflection region 42, a reflection film having a high light reflectance is provided on the measurement surface main body region 43. Further, an antireflection film having a low light reflectance may be provided. Note that a reflective film is provided on the measurement surface main body region 43 and the reflectance of the light in the different reflection region 42 is lowered by increasing the surface roughness of the different reflection region 42, thereby making it different from the measurement surface main body region 43. The light reflectance may be different from that of the reflective region 42. In addition, an antireflection film is provided in the different reflection region 42, and the measurement surface portion main body region 43 has a higher light reflectivity by reducing the surface roughness, so that the measurement surface portion main body region 43 and the different reflection region 42. The reflectance of light may be different. In addition, when the reflectance of light is made different between the measurement surface main body region 43 and the irregular reflection region 42, both the increase and the suppression of the reflectance are not performed, but only one of them is performed. Good.

  According to the resin lens 1 as described above, when the inclination of the resin lens 1 is measured, the light reflected from the measurement surface portion 41 due to the measurement surface portion 41 being shaken due to the distortion of the surface or the position of the reflectance. Even if the light cannot be condensed at substantially one point, the reflectivity between the measurement surface portion main body region 43 and the different reflection region 42 due to the difference in reflectivity depending on the position when the measurement surface portion 41 is a conventional mirror surface portion as described above. The difference is greater. As a result, for example, four clearly dark regions based on the different reflection regions 42 are generated in the shape of the light that is collected and applied to the optical sensor. As a result, four dark regions are arranged along the substantially circumferential direction of the light shape in the shape of the condensed light, so that the cross portion of the cross becomes a shape close to a cross. By considering the measurement surface portion 41 as a light spot when the light is condensed at approximately one point, it is possible to improve the accuracy of measurement of the inclination of the resin lens.

Next, a second embodiment of the present invention will be described.
As shown in FIG. 2, the resin lens 1a of 2nd Embodiment is the same as that of 1st Embodiment except the structure of the measurement surface part 41a.
In the second embodiment, the different reflection area 42a of the measurement surface portion 41a extends from the outer periphery to the inner periphery of the ring-shaped measurement surface portion 41a as in the first embodiment, and both the outer periphery and the inner periphery. The different reflection area 42a does not include the inner peripheral edge portion of the measurement surface portion 41a but includes the outer peripheral edge portion.

Accordingly, the measurement surface portion main body region 43a is not divided by the different reflection region 42a as in the first embodiment, but is integrated. In the second embodiment, the width in the radial direction of the resin lens 1 of the different reflection region 42a is narrowed and becomes the outer periphery of the measurement surface portion 41a, and the reflected light of the measurement surface portion 41a is condensed, and approximately one point. When the light is not condensed, there is a possibility that the shape of the reflected light that has been condensed has a slightly different influence from the case of the first embodiment.
However, the basic influence on the shape of the collected reflected light is substantially the same as that of the first embodiment described above, and the resin lens 1a of the second embodiment is also excellent as in the first embodiment. It is possible to achieve the operational effects.

Next, a third embodiment of the present invention will be described.
As shown in FIG. 3, the resin lens 1b of the third embodiment is the same as that of the first embodiment except for the configuration of the measurement surface portion 41b.
In the third embodiment, the different reflection region 42b of the measurement surface portion 41b extends from the outer periphery to the inner periphery of the ring-shaped measurement surface portion 41b as in the first embodiment. It is not configured to include both, and the different reflection region 42b does not include the outer peripheral edge portion of the measurement surface portion 41b but includes the inner peripheral edge portion.

Therefore, the measurement surface main body region 43b is not divided by the different reflection region 42b as in the first embodiment, but is integrated. In the third embodiment, the width in the radial direction of the resin lens 1 of the different reflection region 42b is narrow and is from the inner periphery of the measurement surface portion 41b, and the reflected light of the measurement surface portion 41b is condensed, When the light is not collected at one point, the shape of the reflected light collected may have a slightly different influence from the case of the first embodiment.
However, the basic influence on the shape of the collected reflected light is substantially the same as in the first embodiment described above, and the resin lens 1b of the third embodiment is also excellent as in the first embodiment. It is possible to achieve the operational effects.

Next, a fourth embodiment of the present invention will be described.
As shown in FIG. 4, the resin lens 1c according to the fourth embodiment reflects light from the measurement surface portions 41, 41a and 41b (measurement surface portion main body regions 43, 43a and 43b) in the first to third embodiments. The reflectance is increased and the light reflectance of the different reflection regions 42, 42a and 42b is suppressed, whereas the light reflectance of the measurement surface portion 41c (measurement surface portion main body region 43c) is suppressed, The light reflectance of the reflection region 42c is increased. The resin lens 1c has the same configuration as that of the first embodiment except for the measurement surface portion 41c.

Further, the method for increasing the reflectance and the method for suppressing the reflectance in the measurement surface portion main body region 43c of the measurement surface portion 41c and the different reflection region 42c are the same as in the first embodiment. Further, the shape of the measurement surface portion main body region 43c and the different reflection region 42c of the measurement surface portion 41c is the same as that of the first embodiment.
In the fourth embodiment, the portion with high light reflectance and the portion with low light reflectance in the measurement surface portion 41c are opposite to those in the first embodiment, and the value of the area of the portion with high light reflectance. And the value of the area of the low light reflectance portion is opposite to that of the first embodiment.

  As a result, the amount of reflected light from the measurement surface portion 41c changes, but the different reflection regions 42c are arranged side by side in the circumferential direction of the annular measurement surface portion 41 formed around the optical functional surface. Basically, the portion between the different reflection regions 42c is also arranged in the same number as the number of the different reflection regions 42c, and in the measurement surface portion 41, a region between the different reflection regions 42c and the different reflection regions 42. Are arranged in substantially the same manner. Even if the high and low reflectivity of the region between the different reflection region 42c and the different reflection region 42 is reversed, the high reflectivity region and the low reflectivity region are alternately arranged in the circumferential direction. The configuration will not change. Therefore, also in the fourth embodiment, the same excellent effects as those in the first embodiment can be achieved.

Next, a fifth embodiment of the present invention will be described.
As shown in FIGS. 5 and 6, the resin lens 1 d of the fifth embodiment has the same configuration as the first embodiment except for the measurement surface portion 41 d having the different reflection region 42 d and the measurement main body region 43 d. Yes. In the first to fourth embodiments, the light reflectance is different between the measurement surface main body regions 43, 43a, 43b, 43c and the different reflection regions 42, 42a, 42b, 42c. In the embodiment, the measurement surface portion main body region 43d and the different reflection region 42d have different reflection directions.

  In the fifth embodiment, the measurement surface portion main body region 43d that is a portion other than the different reflection region 42d of the measurement surface portion 41d is a surface orthogonal to the optical axis of the optical function portion 2 that functions as a pickup lens. Yes. Therefore, for example, the light incident on the measurement surface portion main body region 43d along the optical axis direction has an incident angle to the measurement surface portion main body region 43d of 90 degrees, and the reflected light of this light is incident on the optical axis. It will be along.

  On the other hand, the plane constituting the surface of the different reflection area 42d is not perpendicular to the optical axis but is inclined. In this example, the surface of the different reflection region 42d is inclined so as to become lower from the center side toward the outside in the radial direction of the resin lens 1d. Therefore, the light incident on the different reflection region 42d along the optical axis direction has an incident angle to the different reflection region 42d larger than 90 degrees, for example, and the reflected light of this light is oblique to the optical axis. For example, it is inclined from the center side to the outer peripheral side along the radial direction of the resin lens 1d.

  Therefore, when the light incident on the measurement surface portion 41d along the optical axis direction is condensed by a condensing optical system such as a condensing lens, all of the light reflected by the different reflection region 42d of the measurement surface portion 41d or A part of the light falls outside the range of the condenser lens and is not condensed. Thus, as in the first embodiment, the shape of the collected light when the light reflected and collected by the measurement surface portion 41d is not collected at a substantially single point is formed in the different reflection region 42d. Corresponding dark portions exist, and the same excellent effects as those in the first embodiment can be obtained.

  The different reflection region 42d having a surface angle different from that of the measurement surface portion main body region 43d is, for example, a mold having a molding surface for forming the measurement surface portion 41d, for example, a fixed mold frame of a movable mold frame and a fixed mold frame. It is formed by the molding surface of the nest 72. Therefore, on the molding surface of the nest 72, the portion for molding the measurement surface portion 41d is inclined with respect to the measurement surface portion main body region 41, and the projection amount increases from the inner circumference side toward the outer circumference side. The molding surface is formed.

Thereby, the above-mentioned different reflection area 42d is formed. However, since the nest 72 is used by being rotated, in this case, for example, the positions of the different reflection regions 42 d with respect to the gate cutting part 50 differ depending on the rotation angle of the nest 72.
The gate cutting part 50 has a shape that differs only in the gate cutting part 50 part in the flange part 3 whose outer periphery is substantially circular, and is filled with resin from this part. Therefore, the gate cutting part 50 is measured in the vicinity of the gate cutting part 50. There is a possibility that the distortion of the surface of the working surface portion 41d becomes large. In this case, it may be preferable that the positions of the different reflection regions 42d are the same in each resin lens manufactured with respect to the gate cutting part 50.

  Therefore, the cost is preferably provided with a shape for forming the different reflection region 42d on the molding surface of the nesting 72, but the measurement surface portion 41d is the same as the molding surface of the nesting 72 including the portion to be the different reflection region 42d. It is also possible to mold into two planes, and after molding the resin lens 1d, the post-processing may be cut to form the different reflection region 42d.

The light reflectance of the measurement surface portion main body region 43d and the different reflection region 42d may be the same. However, the different reflection region 42d does not need to have a high reflectance, and is different from the measurement surface portion main body region 43d. The reflectance of the region 42d may be low.
That is, when forming the different reflection region 42d by the insert 72, it is not necessary to mirror-finish the molding surface for forming the different reflection region 42d of the insert 72. Further, it is not necessary to mirror finish the cut portion of the resin lens 1d during post-processing.
Therefore, as in the first embodiment, the reflectance of the different reflection region 42d may be lower than the measurement surface portion main body region 43d.
Further, the surface of the different reflection region 42d is not necessarily a flat surface, and may be a curved surface.

Next, a sixth embodiment of the present invention will be described.
Here, in the first to fourth embodiments, the measurement surface portions 41 and 41a to 41c are planes orthogonal to the optical axis, but as shown in FIG. The measurement surface portion 41e is not a plane orthogonal to the optical axis, and is a slope that becomes lower from the outer peripheral side toward the inner peripheral side. That is, it has the same shape as the inner peripheral surface of the truncated conical recess. However, the angle of the measurement surface portion 41e is small with respect to the plane orthogonal to the optical axis.

The configuration other than the measurement surface portion 4 is the same as any one of the configurations of the first to fourth embodiments.
In the resin lens of the sixth embodiment, even if there is a distortion of the surface of the measurement surface portion 41e, the reflected light from the measurement surface portion 41e can be reliably radiated to the light receiving sensor. The accuracy can be improved. In addition to the degree of distortion of the surface of the resin lens, the area of the light irradiated to the optical sensor tends to be reduced in consideration of a condensing optical system such as a condensing lens when measuring the inclination of the optical axis. It is necessary to determine the angle of the measurement surface portion 41e so that
In the case of the fifth embodiment, the same effect can be obtained if the measurement surface main body region 43e excluding the different reflection region 42e is configured as described above.

Next, a seventh embodiment of the present invention will be described.
As shown in FIG. 8, in the seventh embodiment, the antireflection film 61 is provided in an annular shape in the configuration of the first embodiment. Thereby, without changing the shape of the resin lens 1, the area of the portion of the measurement surface portion 41 that reflects the light can be arbitrarily set, and the reflected light of the measurement surface portion 41 can be reflected by the annular antireflection film 61. When measuring the tilt of the resin lens 1 by condensing and irradiating the optical sensor, if the reflected light applied to the optical sensor is not collected at one point, the shape of the condensed reflected light is reduced. It becomes possible to do.

In FIG. 8, the antireflection film 61 is provided in an annular shape on the outer peripheral side of the measurement surface portion 41, but may be provided in an annular shape on the inner peripheral side of the measurement surface portion 41.
Moreover, it is good also as a structure which provides the cyclic | annular antireflection film 61 in the measurement surface parts 41, 41a, 41b, 41c, 41d, and 41e of 2nd Embodiment-6th Embodiment.
The optical function surface 21 may be provided with an antireflection film for effectively using a laser beam used for reading and writing on the disk. Also good. For example, when the antireflection film 61 is provided on the inner peripheral side of the measurement surface portion 41, the antireflection film can be simultaneously formed on the optical function surface 21 and the inner peripheral portion of the measurement surface portion 41.
In addition, when an antireflection film is applied to the optical function surface 21, it is necessary to apply an antireflection film not only to the optical function surface 21 but also to a part of the measurement surface portion 41 depending on the lens shape and production reasons. There is. Even in such a case, it is desirable that the antireflection film has a substantially circular shape. For example, in the case of a rectangular shape or a line shape, the reflected light from the measurement surface portion 41 is affected by the shape of the antireflection film, and the condensing shape becomes indefinite, which reduces the invention effect.

Next, an eighth embodiment of the present invention will be described.
As shown in FIG. 9, in the resin lens 1f of the eighth embodiment, the measurement surface portion 41f of the resin lens 1f substantially similar to the first embodiment is provided with three different reflection regions 42f instead of four. There are other configurations, which are the same as those of the resin lens 1 of the first embodiment. A region other than the different reflection region 42f of the measurement surface portion 41f is set as a measurement surface portion main body region 43f, and the different reflection regions 42f are arranged in the annular measurement surface portion main body region 43f at substantially equal intervals in the circumferential direction. .

  By providing the three different reflection regions 42f on the measurement surface portion 41f, when the inclination of the resin lens 1f is measured as described above, three dark regions are generated in the collected reflected light. In this case, when the number of the different reflection regions 42f is four, the shape of the reflected light that has been collected cannot be a cross, but it can be a shape having three protrusions, and the reflected light that has been collected. It is possible to make the shape of light easy to obtain at the center. Thereby, the measurement accuracy of the inclination of the resin lens 1f can be improved. When there are two different reflection regions, the shape of the collected reflected light is difficult to obtain the center easily, and it is necessary to have three or more different reflection regions. In the measurement surface portions 41, 41a, 41b, 41c, 41d, and 41e of the second to sixth embodiments, the number of the different reflection areas 42, 42a, 42b, 42c, 42d, and 42e may be three.

1, 1a, 1b, 1c, 1d, 1e, 1f Resin lens 2 Optical function part 41, 41a, 41b, 41c, 41d, 41e, 41f Measuring surface part 42, 42a, 42b, 42c, 42d, 42e, 42f Reflection area 43, 43a, 43b, 43c, 43d, 43e, 43f Measurement surface main body area

Claims (6)

An optical function unit having an optical function, and a measurement surface unit provided around the optical function unit and capable of measuring the inclination of the optical axis of the optical function unit based on reflection of light. ,
The measurement surface portion is provided with a different reflection region,
The different reflection area is set to have a light reflectance and / or a light reflection direction different from those of the measurement surface main body area which is an area of the measurement surface area other than the different reflection area, and the optical Three or more resin lenses are provided at intervals in the circumferential direction of the functional part.   The measurement surface portion is formed in an annular shape, and the different reflection region is a region including a range from the outer periphery to the inner periphery of the measurement surface portion, and a region including the inner periphery without including the outer periphery of the measurement surface portion. 2. The resin lens according to claim 1, wherein the resin lens is provided in any one of regions including an outer peripheral edge not including an inner peripheral edge of the measurement surface portion.   The said different reflection area | region is formed by increasing a reflectance relatively with respect to the said surface part main body area | region for a measurement, or suppressing a reflectance, The Claim 1 or Claim 2 characterized by the above-mentioned. Resin lens.   4. The resin lens according to claim 1, wherein four different reflection regions are formed on the measurement surface portion. 5.   The measurement surface portion is formed in an annular shape, and the measurement surface portion main body region is set to have a higher reflectance than the irregular reflection region, and a part of the measurement surface portion is arranged in the circumferential direction of the measurement surface portion. The resin lens according to claim 1, further comprising an annular antireflection film that covers the resin lens.   6. The resin lens according to claim 1, wherein the measurement surface portion is formed on an inclined surface that is recessed from the outer peripheral side toward the inner peripheral side.

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