JP2023038751A - Optical component and optical component loading device - Google Patents

Abstract

To provide an optical component that has an adhesive structure of an optical lens and a metal housing using a low cure shrinkage UV curable adhesive, and prevents positional deviation over time in use environments (high temperature, high temperature and high humidity, and temperature cycle) to allow high positional accuracy.SOLUTION: In an optical component having an adhesion part formed of an adhesive structure that bonds and fixes an optical lens and a metal housing using a UV curable adhesive including a filler formed of metal oxide in an amount of 50 mass% or more and at least one or more types of adhesives, the adhesion part is such that the UV curable adhesive satisfying the following first requirement and second requirement is arranged at a center part, and 50% or more of a surface of the UV curable adhesive not including a part to be bonded with an addition polymerization silicone rubber adhesive satisfying the following third requirement. First requirement: a water absorption of 0.5% or less in an environment of 85°C and 85%; second requirement: Tg of 105°C or more; third requirement: a heat loss of 0.3% or less in an environment of 105°C.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical component and an optical component mounting device.

2. Description of the Related Art Optical components applicable to optical component mounting devices such as head-up displays are known. For fixing the position of optical parts (lenses, etc.), UV curable adhesives are often used because of their low curing shrinkage, short curing time, and good productivity. Cationic polymerization adhesives are often used.

The installation of optical components may require a positioning accuracy that does not allow even minute displacements of several μm within a storage temperature range of -40° C. to +60° C., for example. However, the adhesive used to fix the optical component to the holding member is affected by moisture and fine dust in the air, or deteriorates over time. . For this reason, the fixed state also changes, and the fixed optical component may be slightly misaligned.

As a technology to solve the above conventional problems, the part of the UV curable adhesive that is exposed to the outside is covered with a coating material (silicon resin, epoxy resin, etc.) to remove moisture and fine dust from UV. A technique for preventing contact with a curable adhesive is known (see Patent Document 1).

According to the technique disclosed in Patent Document 1, for example, in the storage temperature range (−40° C. to +60° C.) of the optical component, it is possible to prevent displacement over time due to the reaction of the UV curable adhesive. However, there is a problem in using the technique of Patent Document 1 for optical components employed in in-vehicle equipment.

For example, a case is assumed in which parts using a UV-curing adhesive such as an acrylic radical polymerization adhesive or an epoxy cationic polymerization adhesive are applied to in-vehicle equipment. In this case, it is possible to suppress positional displacement over time in a temperature cycle environment within the storage temperature range (−40° C. to +105° C.) of the in-vehicle device or in a high temperature and high humidity (85° C. 85%) environment.

In general, at a high temperature of 105° C. (the highest temperature in the storage temperature range) for a long period of time, oxygen is activated into oxygen radicals, which may attack polymeric materials. And UV curable adhesives are susceptible to attack by activated oxygen radicals. Therefore, under high temperature for a long period of time, heat loss occurs due to volatilization and oxidative decomposition of the initiator and additives of the UV curable adhesive. Therefore, in a long-term environment of 105° C., the UV curable adhesive shrinks due to heat loss, resulting in displacement over time.

That is, in a long-term 105° C. environment, it is necessary to limit the physical properties (Tg, heat loss) of the adhesive, but the prior art including Patent Document 1 does not consider the physical properties of the adhesive. Therefore, when the conventional technology is applied to an optical component in a long-term 105° C. environment, there is a problem in reliably preventing the displacement over time.

In addition, assuming that the optical component mounting device is an in-vehicle device, the environment in which the in-vehicle device is used is hot and humid (85° C. 85%), and the optical components are required to have durability in this environment. That is, durability in an environment that is more severe than the general high humidity and high temperature (45° C. 90%) premised on the technique disclosed in Patent Document 1 is required.

In addition, long-term durability is required for in-vehicle equipment rather than optical pickup parts such as those exemplified in Patent Document 1. In this regard, since the technique disclosed in Patent Document 1 does not consider the moisture-proof function of the covering material, moisture permeates the covering material. Therefore, although the technology disclosed in Patent Document 1 can delay the permeation of moisture into the UV-curable adhesive, it is insufficient for the useful life of the in-vehicle equipment. Therefore, when the technique disclosed in Patent Document 1 is applied to an optical component employed in an on-vehicle device, moisture permeates the UV-curing adhesive, causing swelling due to water absorption, which may cause misalignment. That is, the prior art including Patent Document 1 has a problem in that it is necessary to limit the water absorption rate of the adhesive under high temperature and high humidity conditions for a long period of time.

As described above, in the prior art, consideration of the physical properties of the UV curable adhesive is unknown. There is a problem in using it for parts that require reliable prevention of displacement.

The present invention has a bonding structure between an optical lens and a metal housing using a UV curable adhesive with low curing shrinkage, and suppresses displacement over time in a usage environment (high temperature, high temperature and high humidity, temperature cycle). It is an object of the present invention to provide an optical component capable of achieving high positional accuracy.

In order to solve the above technical problem, in one aspect of the present invention, an optical lens and a metal housing are adjoined by a UV curable adhesive containing 50% by mass or more of a filler made of a metal oxide and at least one adhesive. An optical component having an adhesive part consisting of an adhesive structure that adheres and fixes the adhesive part, wherein the adhesive part has a UV curable adhesive that satisfies the following first and second requirements at the center, and the part to be adhered is It is characterized in that 50% or more of the surface of the UV curable adhesive that does not contain a UV curable adhesive is covered with an addition polymerization silicone rubber adhesive that satisfies the following third requirement.
1st requirement: 0.5% or less water absorption in 85°C 85% environment 2nd requirement: Tg 105°C or higher 3rd requirement: 0.3% or less heating loss in 105°C environment

According to the present invention, it has an optical lens and a metal housing bonded structure using a UV curable adhesive with low curing shrinkage, suppressing displacement over time in the usage environment (high temperature, high temperature and high humidity, temperature cycle). By doing so, high position accuracy is possible.

FIG. 2 is a diagram showing a structural example of an embodiment of an optical component according to the present invention; 4 is a graph for explaining properties of a UV curable adhesive used for the optical component. 4 is a graph for explaining properties of a UV curable adhesive used for the optical component. 4 is a graph for explaining the properties of the addition-polymerization type silicone rubber adhesive used for the optical component. 4 is a graph for explaining the properties of the addition-polymerization type silicone rubber adhesive used for the optical component. The figure explaining the 1st Example of the said optical component. 4A and 4B are diagrams for explaining a bonding process in the optical component according to the first embodiment; FIG. FIG. 4 is a diagram illustrating the film pressure direction in the first embodiment of the optical component; FIG. 10 is a table showing the evaluation results of misalignment in each test performed using a plurality of examples and comparative examples of the optical component according to the embodiment; The top view which shows embodiment of the optical component mounting apparatus provided with the said embodiment. The block diagram of the said optical component mounting apparatus.

[Adhesion structure]
FIG. 1 is a front view (a) and a side view (b) showing a structural example of an optical lens structure 10 as an embodiment of an optical component according to the present invention. As shown in FIG. 1, the optical lens structure 10 according to the present embodiment includes an optical lens 1 which is a type of optical component, a metal housing 2 as a fixed member for fixing the optical component, and a UV curable adhesive. It has an agent 3 and an addition polymerization type silicone rubber adhesive 4 .

The metal housing 2 is a holding member for fixing and holding the optical lens 1 at a predetermined position and state. The UV curable adhesive 3 is an adhesive member for fixing the optical lens 1 to the metal housing 2 . The addition polymerization type silicone rubber adhesive 4 is a coating material that covers the surface of the UV curable adhesive 3, excluding the portion where the UV curable adhesive 3 adheres to the object to be adhered (the optical lens 1 and the metal housing 2). is.

[Optical component mounting device]
Here, a configuration example of a head-up display device 100 as an in-vehicle device will be described with reference to FIGS. . FIG. 10 is a plan view of the head-up display device 100. FIG. FIG. 11 is a diagram showing an example of the configuration of a display device 101 including the optical lens structure 10. As shown in FIG.

As shown in FIG. 10 , a head-up display device 100 includes a display device 101 as an example of utilization of the optical lens structure 10 and a free-form surface mirror 103 . The display device 101 also includes a light source device 11 , an optical deflection device 13 and a screen 15 .

The light source device 11 is a device that emits laser light emitted from a light source to the outside of the device. The light source device 11 may irradiate a laser beam obtained by synthesizing three colors of R, G, and B laser beams, for example.

The light deflection device 13 is an example of an image forming unit that receives irradiation light emitted from the light source device 11 and emits image light for forming an image. It is a device that changes the traveling direction of light.

The screen 15 is an example of a member on which an image is formed by imaging the image light emitted from the optical deflection device 13, and is a diverging member having a function of diverging the laser light at a predetermined divergence angle. The screen 15 is, for example, in the form of an EPE (Exit Pupil Expander) and is composed of a transmissive optical element having a light diffusion effect such as a microlens array (MLA) or a diffusion plate.

Here, the projection method of the display device 101 is a “panel method” in which an intermediate image is formed by an imaging device such as a liquid crystal panel, a DMD panel (digital mirror device panel), or a vacuum fluorescent display (VFD). There is a "laser scanning method" in which an intermediate image is formed by scanning a laser beam with a scanning means.

FIG. 11 is a diagram showing an example of the configuration of the display device 101. As shown in FIG. In addition to the light source device 11, the optical deflection device 13, and the screen 15 described with reference to FIG. A condenser lens 410 for condensing the modulated light toward the light deflector 13 , a mirror 401 for reflecting the polarized light deflected by the light deflector 13 , and a reflected light reflected by the mirror 401 toward the screen 15 . It further comprises a reflective second mirror 402 .

The light source device 11 includes light source elements 111R, 111G, and 111B (hereinafter referred to as light source elements 111 when there is no need to distinguish them), collimator lenses 112R, 112G, and 112B, apertures 113R, 113G, and 113B, a combining element 114, 115 , 116 and lens 117 .

The light source elements 111R, 111G, and 111B that emit three-color (R, G, and B) laser beams are, for example, LDs (Laser Diodes) each having a single or a plurality of light emitting points. The light source elements 111R, 111G, and 111B emit laser light (luminous flux) with different wavelengths λR, λG, and λB (eg, λR=640 nm, λG=530 nm, and λB=445 nm).

The emitted laser beams (luminous fluxes) are coupled by collimator lenses 112R, 112G, and 112B, respectively, to form substantially parallel luminous fluxes. Each coupled laser (light beam) is combined by three combining elements 114 , 115 , 116 . The synthesizing elements 114, 115, and 116 are plate-shaped or prism-shaped dichroic mirrors that reflect or transmit the laser beams (luminous fluxes) according to their wavelengths and synthesize them into one luminous flux. The combined luminous flux passes through the filter 307 and the condenser lens 410 and is guided to the optical deflection device 13 .

The display device 101 is configured by assembling a housing 10A, a mirror unit (mirror holding member) 305, and a screen unit 300. As shown in FIG. The housing 10A holds and accommodates the light source elements 111R, 111G and 111B, the collimator lenses 112R, 112G and 112B, the synthesizing elements 114, 115 and 116, the filter 307, the condensing lens 410 and the light deflection device 13. A mirror unit 305 holds a mirror 401 and a second mirror 402 . The screen unit 300 is an example of a holding member that holds the screen 15 .

The light source unit 110 is detachable from the housing 10A and holds light source elements 111R, 111G, and 111B.

[Regarding the positional accuracy required for in-vehicle environments]
A case is assumed in which the head-up display device 100 described above is mounted on a vehicle. In order to ensure the optical characteristics of the head-up display device 100, it is necessary to fix the head-up display device 100 to an adherend such as a vehicle housing after adjusting (aligning) the position with other optical components. Therefore, after the alignment of the optical lens 1 included in the optical lens structure 10, the UV curable adhesive 3, which can be cured immediately, is often used. Therefore, the UV curable adhesive 3 is required to have low cure shrinkage and high positional accuracy under the following storage environment.

First condition: high temperature (105°C)
Second condition: Temperature cycle within a specified temperature range (-40°C to +105°C)
Third condition: High temperature and high humidity (85°C 85%)

In addition, in a structure in which an optical lens 1 as an optical component is adhered to a metal housing 2 as an adherend to which it is fixed (hereinafter sometimes referred to as "optical component adhesion"), the optical lens 1 as an optical component , the adhesive layer thickness fluctuates by about 100 μm to 400 μm. In order to achieve high positional accuracy under each environment even if the thickness of the adhesive layer fluctuates, it is necessary to suppress the displacement over time under each environment to ±1% or less of the thickness of the adhesive layer. For example, in the case of 200 μm, it is necessary to suppress the temporal positional deviation to ±200 μm or less.

[About adhesive]
Next, properties of the UV curable adhesive 3 according to this embodiment will be described. As the UV-curing adhesive 3, for example, an epoxy-based, acrylic-based, or other UV-curing adhesive containing 50% by mass or more of a filler made of a metal oxide such as silica can be applied. Generally, by filling the adhesive with a silica filler, low cure shrinkage during UV irradiation becomes possible.

In addition, the UV curable adhesive 3 is configured to satisfy the following first and second requirements. Details will be explained.

1st requirement: 0.5% or less water absorption in 85°C 85% environment 2nd requirement: Tg 105°C or higher

[Regarding water absorption of 0.5% or less in an environment of 85°C and 85%]
The measurement of the water absorption included in the first requirement for the UV curable adhesive 3 according to this embodiment is performed by the following method. That is, the weight before the test and the weight after being left at 85° C. 85% for 1000 hours are measured using a single cured product of the produced UV curable adhesive 3 . The water absorption is calculated by the following formula (1) using the measured weight.

(Formula 1)
Water absorption [%] = 100 x (weight after 85°C 85% 1000 hours - weight before test) / weight before test

Here, the relationship between the water absorption rate and the positional displacement over time will be described using the graph of FIG. In the graph of FIG. 2, the horizontal axis represents the water absorption rate of the UV curable adhesive 3 in the 85° C. 85% environment, and the vertical axis represents the displacement of the UV curable adhesive 3 in the 85° C. 85% environment over time. When the positional deviation over time is ±1% or less of the adhesive layer thickness, it is plotted as "O", and when it is ±1% or more of the adhesive layer thickness, it is plotted as "x".

In an environment of 85° C. and 85%, the UV curable adhesive 3 absorbs water and swells. Therefore, as the water absorption rate of the UV curable adhesive 3 increases in an environment of 85° C. and 85%, the displacement over time increases due to the effect of water absorption swelling. If the UV curable adhesive 3 has a water absorption rate of 0.5% or less in an 85° C. 85% environment, it is possible to ensure a temporal displacement of ±1% or less in an 85° C. 85% environment.

[Regarding Tg of 105°C or higher]
Next, a method for measuring Tg, which is included in the second requirement for the UV curable adhesive 3 according to this embodiment, will be described. In the present embodiment, the UV curable adhesive 3 is used as a single cured adhesive to measure the glass transition temperature by TMA. Then, based on the measurement result, the inflection point temperature derived from the glass transition temperature is determined as Tg.

Here, the relationship between the time-dependent position shift in a temperature cycle within a predetermined temperature range and Tg will be described with reference to the graph of FIG. In the graph of FIG. 3, the horizontal axis is Tg, and the vertical axis is positional deviation over time in a temperature cycle (-40° C. to +105° C.). When the positional deviation over time is ±1% or less of the adhesive layer thickness, it is plotted with "o", and when it is ±1% or more of the adhesive layer thickness, it is plotted with "x".

If Tg is less than 105° C., the maximum temperature in the storage temperature range, the UV curable adhesive 3 rapidly softens in a temperature environment equal to or higher than Tg. Therefore, in a temperature environment equal to or higher than Tg, the UV curable adhesive 3 cannot withstand the internal stress due to the weight of the optical lens 1, etc., so that the adhesive layer of the UV curable adhesive 3 is compressed and deformed. positional deviation occurs.

On the other hand, when the Tg of the UV curable adhesive 3 is 105° C. or higher, the Tg is not exceeded in the storage temperature range, so rapid softening of the UV curable adhesive 3 can be prevented, and the internal stress of the UV curable adhesive 3 can be prevented. Since 3 is not inferior, it is possible to secure ±1% or less of positional deviation over time. For these reasons, in order to achieve high positional accuracy in each environment (high temperature, high temperature and high humidity, temperature cycle), the Tg of the UV curable adhesive 3 is specified at the maximum temperature of 105 ° C or higher in each environment. There is a need to.

[Positional displacement of the UV curable adhesive 3 over time in a long-term 105° C. environment]
The UV curable adhesive 3 configured to satisfy the above first requirement and second requirement suppresses displacement over time in an 85° C. 85% environment and a temperature cycle (-40° C. to +105° C.) environment. be able to. Compared to the temperature cycle (−40° C. to +105° C.) environment, the environment in which the UV curable adhesive 3 is exposed is the 105° C. environment, and in the long term, oxygen is activated to become oxygen radicals, resulting in high temperature. May attack molecular materials.

Since the UV curable adhesive 3 is easily attacked by activated oxygen radicals, heat loss occurs due to volatilization and oxidative decomposition of the initiator and additives of the UV curable adhesive 3 in a long-term 105° C. environment. Therefore, in a long-term environment of 105° C., the UV curable adhesive 3 shrinks due to heat loss, resulting in displacement over time.

Therefore, in the optical lens structure 10 according to the present embodiment, the surface of the UV curable adhesive 3 that does not include the bonding portion (bonding portion) between the optical lens 1 and the metal housing 2 as bonding objects is subjected to the third requirement. is coated with an addition polymerization type silicone rubber adhesive 4 composed of As a result, it is possible to prevent heat loss of the UV curing adhesive 3 in a long-term 105° C. environment and suppress positional displacement over time in a long-term 105° C. environment. Details of the addition polymerization type silicone rubber adhesive 4 will be described below.

[Regarding addition polymerization type silicone rubber adhesive 4]
Generally, silicone rubber adhesives are known to be of condensation polymerization type and addition polymerization type. Condensation-polymerized silicone rubber generates a small amount of outgas such as acetone, alcohol, and oxime during the reaction. Therefore, the present embodiment is limited to addition polymerization type silicone rubber adhesives. As the addition polymerization type silicone rubber adhesive 4, a thermosetting or room temperature curing addition polymerization type silicone rubber adhesive can be applied.

Since silicone rubber is less likely to be attacked by oxygen radicals activated in a 105°C environment, the surface of the UV curable adhesive 3 that does not include the adhesive portion with the adhesion target (optical lens 1 and metal housing 2) is added. By coating with the polymerizable silicone rubber adhesive 4, it acts as follows in a 105° C. environment. That is, the activated oxygen radicals are adsorbed or consumed by the addition polymerization type silicone rubber adhesive 4 , so that the oxygen radicals do not reach the UV curable adhesive 3 .

Therefore, even in a long-term environment of 105° C., oxygen does not come into direct contact with the UV curable adhesive 3, so that volatilization and oxidative decomposition of the initiator and additives of the UV curable adhesive 3 can be prevented. It is possible to prevent shrinkage due to heat loss.

Since silicone rubber adhesives generally have high moisture resistance, the addition polymerization type silicone rubber adhesive 4 does not have a water absorption rate of 85° C. 85% environment like the UV curable adhesive 3 stipulated. In general, silicone rubber adhesives have a Tg of −40° C. or lower, and always Tg of silicone rubber adhesives or higher under storage conditions (−40° C. to +105° C.). When the storage environment temperature straddles Tg, the adhesive will soften rapidly if it exceeds Tg. If the storage environment (-40°C to +105°C) is always Tg or higher, the temperature does not cross Tg and the adhesive does not soften rapidly. The same Tg as Adhesive 3 is not specified.

The addition polymerization type silicone rubber adhesive 4 having the properties described above is composed of the following third requirements. A detailed description will be given below.

3rd requirement = 0.3% or less heating loss in 105°C environment

[Regarding heating loss of 0.3% or less in a 105 ° C environment]
The heating loss of the addition polymerization type silicone rubber adhesive 4 in a 105° C. environment is measured by the following method. That is, the weight of the prepared single cured product of the addition polymerization type silicone rubber adhesive 4 before the test and the weight after standing at 105° C. for 1000 hours are measured. Using the measured weight, the weight loss on heating in a 105° C. environment is calculated according to the following formula (2).

formula (2)
Loss on heating [%] = 100 x (weight before test - weight after 1000 hours at 105°C) / weight before test

Here, properties of the addition polymerization type silicone rubber adhesive 4 will be described with reference to the graph of FIG. In the graph of FIG. 4, the horizontal axis indicates the heating weight loss in the 105° C. environment. The vertical axis represents the adhesion structure in which the surface of the UV-curing adhesive 3 that does not include the adhesive portion of the adhesion target (the optical lens 1 and the metal housing 2) is completely covered with the addition polymerization silicone rubber adhesive 4. It shows the positional displacement over time in a 105° C. environment.

When the time-dependent misalignment is ±1% or less of the adhesive layer thickness, it is plotted with “◯”, and when it is ±1% or more of the adhesive layer thickness, it is plotted with “x”.

In a long-term 105° C. environment, heat loss occurs due to volatilization and oxidative decomposition of initiators and additives in the adhesive. Therefore, the greater the heat loss of the addition polymerization type silicone rubber adhesive 4, the greater the shrinkage of the adhesive and the greater the displacement over time in the compression direction of the adhesive layer. Therefore, as shown in FIG. 4, if the addition polymerization type silicone rubber adhesive 4 has a heat loss of 0.3% or less in a 105° C. environment, it ensures a time-dependent displacement of ±1% or less in a 105° C. environment. be able to.

If 50% or more of the surface of the UV curable adhesive 3 that does not include the adhesive portion of the adhesion target (optical lens 1 and metal housing 2) is covered with the addition polymerization type silicone rubber adhesive 4, a 105° C. environment high positional accuracy is possible. The details of the coverage will be described below.

[Regarding the Coverage of the Addition Polymerization Type Silicone Rubber Adhesive 4]
The coverage of the addition polymerization type silicone rubber adhesive 4 according to this embodiment can be measured by the following method. That is, using a microscope, the following surface area A and surface area B are measured, and the coverage is calculated using the following formula (3).

Surface area A: The UV curable adhesive 3 that does not include the bonded portion between the optical component and the object to be bonded (the optical lens 1 and the metal housing 2) after the fixation of the optical component and the metal housing is released in the sixth step of the adhesion process described below. Surface area.

Surface area B: The surface of the addition polymerization type silicone rubber adhesive 4 that does not include the adhesive portion with the adhesive object (optical lens 1 and metal housing 2) of silicone rubber adhesive heat curing in the eighth step of the adhesion process described below. to the surface area where the UV curable adhesive 3 is exposed.

Formula (3)
Coverage [%] = 100 x (surface area A - surface area B) / surface area A

Here, using the graph of FIG. 5, the relationship between the coverage of the addition polymerization type silicone rubber adhesive 4 that satisfies the above third requirement and the displacement over time in a 105° C. environment is shown. In the graph of FIG. 5, the horizontal axis indicates the coverage of the addition polymerization type silicone rubber adhesive 4, and the vertical axis indicates the displacement over time in the 105° C. environment. When the positional deviation over time is ±1% or less of the adhesive layer thickness, it is plotted with "o", and when it is ±1% or more of the adhesive layer thickness, it is plotted with "x".

If the coverage of the addition polymerization type silicone rubber adhesive 4 is less than 50%, the oxygen radicals activated in the environment of 105° C. cannot be adsorbed or consumed by the addition polymerization type silicone rubber adhesive 4 . Therefore, as shown in FIG. 5, when the coverage of the addition polymerization type silicone rubber adhesive 4 is less than 50%, oxygen contacts the UV curable adhesive 3, and the initiator and additive of the UV curable adhesive 3 Heat loss occurs due to volatilization and oxidative decomposition of the agent. As a result, shrinkage of the UV curable adhesive 3 causes displacement of the adhesive layer over time in the direction of compression.

Further, if the coverage of the addition polymerization type silicone rubber adhesive 4 is 50% or more, the oxygen radicals activated in the environment of 105° C. can be adsorbed or consumed by the addition polymerization type silicone rubber adhesive 4, and the UV curing type adhesive Heat loss of 3 can be suppressed. Therefore, it is possible to ensure a temporal positional deviation of ±1% or less in a 105° C. environment.

[About the bonding process]
Next, a step (adhesion process) for adhering objects to be adhered (the optical lens 1 and the metal casing 2) according to the present embodiment will be described. The bonding process according to this embodiment has the following first to eighth steps. Each step will be described below.

[First step: surface treatment]
The first step is the surface treatment step. The surface treatment is performed to improve the wettability of the adherend (the optical lens 1 and the metal housing 2) and to improve the bonding strength between the adhesive and the adherend. Surface treatment methods include atmospheric pressure plasma treatment, reduced pressure plasma treatment, corona treatment, plasma treatment, UV treatment and the like.

[Second process: Fixing optical parts and metal housing]
The second step is the “optical component/metal casing fixing” step. This is a step of fixing the surface-treated optical lens 1 and the metal housing 2 at predetermined positions. The fixation is performed using the optical component/metal casing fixing function of the optical component bonding apparatus. Methods for fixing the optical lens 1 include chucks, clamps, and the like, and methods for fixing the metal housing 2 include screw fastening, toggle clamps, and the like.

[Third step: UV adhesive application]
The third step is the UV adhesive application step. The application of the UV curable adhesive 3 is performed using the application function of the optical component bonding apparatus. A dispenser etc. are mentioned as the method of application|coating.

[Fourth step: optical component alignment]
The fourth step is to align the fixed optical lens 1 at a predetermined position, which is an optical component alignment step. Optical component alignment is performed using the position adjustment function of the optical component bonding apparatus. Position adjustment methods include an active alignment device, a precision desktop three-axis robot, and an XYZ-axis linear ball.

[Fifth step: adhesive UV curing]
The fifth step is the adhesive UV curing step. In this step, the applied UV curable adhesive 3 is irradiated with UV from above the optical lens 1 to be cured. UV curing of the adhesive is performed using the UV irradiation function of the optical component bonding apparatus. UV irradiation methods include ultraviolet lamps, visible light lamps, infrared lamps, and the like. Ultraviolet lamps include high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, high-power metal halide lamps, gallium lamps, xenon lamps, xenon flash lamps, excimer lamps, UV-LEDs, and electrodeless lamps. One or two or more UV irradiations may be used as long as the adhesive can be cured.

[Step 6: Fixation of optical components and metal housing released]
The sixth step is the optical component/metal case fixing release step. In this process, after UV curing of the UV curing adhesive 3, the fixation of the optical lens 1 and the metal housing 2 is released and removed from the optical component bonding apparatus. The fixation of the optical lens 1 and the metal housing 2 is released by using the optical component/metal housing fixing function of the optical component bonding apparatus. Methods for fixing the optical lens 1 include chucks, clamps, and the like, and methods for fixing the metal housing 2 include screw fastening, toggle clamps, and the like.

[Seventh step: Application of silicone rubber adhesive]
The seventh step is the silicone rubber adhesive application step. The addition polymerization type silicone rubber adhesive 4 is applied using the application function of the optical component bonding apparatus. A dispenser etc. are mentioned as the method of application|coating.

[Step 8: Thermal curing of silicone rubber adhesive]
The eighth step is a silicone rubber adhesive thermosetting step. In this step, after the addition polymerization type silicone rubber adhesive 4 is applied, it is thermally cured by a heating device. Heating devices include ovens, heater plates, near-infrared halogen lamps, and far-infrared heaters.

[Example 1]
Next, as a first example described in the above embodiment, the optical lens 1 adopts "a collimator lens on an Al housing", the thickness of the adhesive layer with the metal housing 2 is "200 μm", and the adherend An example of fixing will be described.

(glue)
As a first embodiment, an acrylic UV curable adhesive 3 is used as the UV curable adhesive, and a heat curable addition polymerizable silicone rubber adhesive is used as the addition polymerizable silicone rubber adhesive 4. 4 was used. The water absorption and Tg of the UV curable adhesive 3 in an 85° C. 85% environment, and the heat loss evaluation of the heat curable addition polymerization type silicone rubber adhesive 4 in an environment of 105° C. were measured by the following methods.

(Measurement of water absorption in an environment of 85°C and 85%)
The water absorption rate of the UV curable adhesive 3 was measured using an electronic balance (GR-202 (A&D)). The weight after standing for 1000 hours at 85% was measured, and the water absorption rate in the 85° C. 85% environment was calculated using the following formula (4).

Formula (4)
Water absorption [%] = 100 x (weight after 85°C 85% 1000 hours - weight before test) / weight before test

According to the measurement results under the above conditions, the water absorption rate in an environment of 85° C. and 85% was 0.3%.

(Tg measurement)
Tg of the UV curable adhesive 3 was measured using TMA4000SA type (manufactured by Netsch Japan). A single cured product of the UV curable adhesive 3 prepared by measuring the glass transition temperature was measured under the conditions of a width of 4 mm, a length of 20 mm, a load of 10 gf, a temperature increase rate of 10 ° C./min, and an air atmosphere. The temperature at the inflection point was determined as Tg. It was Tg=123 degreeC from the measurement result.

(Measurement of weight loss on heating in a 105°C environment)
An electronic balance GR-202 (A&D) was used to measure the heat loss of the addition polymerization type silicone rubber adhesive 4 in an environment of 105°C. Then, the weight of the single cured product of the prepared addition polymerization type silicone rubber adhesive 4 before the test and the weight after standing at 105°C for 1000 hours were measured, and the following formula (5) was used to calculate the weight in the 105°C environment. Weight loss on heating was determined.

Formula (5)
Loss on heating [%] = 100 x (weight before test - weight after 1000 hours at 105°C) / weight before test

From the measurement results under the above conditions, the weight loss on heating in a 105° C. environment was 0.2%.

(Optical lens 1)
A collimator lens was used as the optical lens 1 . The material of the collimator lens is L-BSL7, the dimensions are Φ5.1, and the thickness is 2.35 mm.

(Metal housing 2)
An Al housing was used for the metal housing 2 . The material of the Al housing is ADC12. The overall dimensions of the Al housing are 13.5 mm×51.8 mm×t2.5 mm.

As shown in FIG. 6, the optical lens structure 10 according to the first embodiment uses a collimator lens having a circular optical surface as the optical lens 1 . As the metal housing 2, an Al housing is used. Then, as shown in FIG. 6, the side surface of the collimator lens is fixed at one point on the surface (flat surface) of the Al housing with an adhesive layer having a thickness of 200 μm. The adhesive layer thickness of 200 μm means that the distance from the surface of the Al housing to the lowest point Lp of the collimator lens is 200 μm.

(adhesion device)
The bonding process in the first embodiment is shown using FIG. An optical component bonding apparatus 200 capable of performing this bonding process includes a holder 210 that holds the optical lens 1, an adhesive applicator 220, and an ultraviolet irradiation tool 230. FIG. The optical component bonding apparatus 200 has an optical component/metal case fixing function, an adhesive application function, a position adjustment function, and a UV irradiation function.

The holder 210 operates as a pair of, for example, a first chuck 211 having grooves formed on one side and a second chuck 212 having a flat surface on one side. The optical component bonding apparatus 200 also has a fixing jig for fixing the metal housing 2 by screwing. The optical component/metal case fixing function is realized by the holder 210 and the fixing jig.

The adhesive applicator 220 is a so-called dispenser, and as a first example, "MS-1D" manufactured by Musashi Engineering Co., Ltd. is used. The adhesive application function is realized by the dispenser.

The position adjustment function uses an XYZ-axis linear ball micrometer head (XYZGS80, manufactured by Misumi Co., Ltd.) to finely adjust the relative positional relationship between the metal housing 2 and the optical lens 1 and to achieve alignment of the optical components. It is realized by

The ultraviolet irradiation tool 230 has a so-called plateau for ultraviolet irradiation, and as a first example, Panasonic's UV-LED curing device (ANUJ3500 (controller)), ANUJ6186 (smart head), ANUJ6428 (φ8 spot lens). take advantage of A UV irradiation function is realized by the ultraviolet irradiation tool 230 .

(Adhesion process according to the first embodiment)
Next, a first example of a step (bonding process) for bonding objects to be bonded (the optical lens 1 and the metal housing 2) according to this embodiment will be described. Note that FIG. 2 shows a process image from the second step to the seventh step.

[First step: surface treatment]
Surface treatment of the metal housing 2 is performed using an atmospheric pressure plasma treatment apparatus (piezo brush PZ2: manufactured by Ars). The surface treatment time was set to a time at which the surface free energy of the collimator lens (optical lens 1) and the Al housing (metal housing 2) increased and the change was saturated. The collimator lens uses a standard nozzle from a distance of 10 mm (manufacturer's recommended distance), and the Al housing uses a near-field nozzle (for conductors) from a distance of 2 mm (manufacturer's recommended distance). Perform surface treatment.

[Second process: Fixing optical parts and metal housing]
As shown in FIG. 7(a), the collimator lens (optical lens 1) is gripped and fixed by the first chucking tool 211 and the second chucking tool 212, and the Al housing (metal housing 2) is bonded to the optical parts. It is fixed with a screw provided with the device 200 . It should be noted that illustration of screws is omitted in FIG.

[Third step: UV adhesive application]
Next, as shown in FIG. 7B, a UV curing adhesive 3 is applied to the surface of the Al housing (metal housing 2). The adhesive is applied by a dispenser (MS-1D, manufactured by Musashi Engineering Co., Ltd.) as the adhesive applicator 220 . The coating amount here was 3 mg, which allows adhesion without adhering to the optically effective range of the collimator lens with an adhesive layer thickness of 200 μm.

[Fourth step: optical component alignment]
Subsequently, as shown in FIG. 7C, the fixed collimator lens is separated from the Al housing by 200 μm by the XYZ-axis linear ball micrometer head (XYZGS80, manufactured by Misumi) provided in the optical component bonding apparatus 200. Adjust to fit. Originally, it is necessary to adjust the position of the collimator lens so that the optical characteristics can be secured.

[Fifth step: adhesive UV curing]
Subsequently, as shown in FIG. 7D, the UV-LED curing device (ANUJ3500 (controller), ANUJ6186 (smart head), ANUJ6428 (φ8 Spot lenses (all manufactured by Panasonic) are used for curing. Light with a wavelength of 365 nm was irradiated as ultraviolet rays from above the collimator lens in two directions.

[Step 6: Fixation of optical components and metal housing released]
Subsequently, as shown in FIG. 7E, after the UV irradiation is completed, the first chucking device 211 and the second chucking device 212 are opened, and the Al housing (metal housing 2) is released from the screw fastening. This completes the operation of removing the optical lens structure 10 from the optical component bonding apparatus 200 and UV curing the collimator lens (optical lens 1) on the Al housing (metal housing 2).

[Seventh step: Application of silicone rubber adhesive]
Subsequently, as shown in FIG. 7(f), an addition polymerization type silicone rubber adhesive 4 was applied to the Al housing (metal housing 2) using a dispenser (MS-1D, manufactured by Musashi Engineering Co., Ltd.). As shown in FIG. 7(f), 3 mg of the UV curable adhesive 3 was applied to both ends.

[Step 8: Thermal curing of silicone rubber adhesive]
Finally, the optical lens structure 10 was heat-treated for 1 hour in an oven (DX302, manufactured by Yamato Scientific Co., Ltd.) at 105°C.

[Second embodiment]
Next, a second example of the embodiment described above will be described. The second embodiment differs from the already explained first embodiment only in the seventh step (silicone rubber adhesive application).

In the seventh step of the second embodiment, 2.0 mg of the addition polymerization type silicone rubber adhesive 4 was applied to each end of the UV curable adhesive 3 . As for other steps, the same steps as those described in the first embodiment were performed to fix the collimator lens to the Al housing.

Hereinafter, comparative examples for explaining the effectiveness of the first and second examples will be described first, and each comparative example will be compared with the first and second examples.

[First comparative example]
In the first comparative example, the UV curable adhesive 3 having a water absorption rate of 1.5% in an 85° C. 85% environment and a Tg of 90° C. in an 85° C. 85% environment was used. Other materials used were the same as those of the first embodiment, and the collimator lens was fixed to the Al housing by the process described in the first embodiment.

[Second comparative example]
In the second comparative example, an addition polymerization type silicone rubber adhesive 4 having a heat loss of 1.2% in a 105° C. environment was used. Other materials used were the same as those of the first embodiment, and the collimator lens was fixed to the Al housing by the process described in the first embodiment.

[Third Comparative Example]
In the third comparative example, in the seventh step (silicone rubber adhesive application process) in the first example, the addition polymerization type silicone rubber adhesive 4 was applied to both ends of the UV curable adhesive 3 in an amount of 1.5 mg each. . Other than this, the collimator lens was fixed to the Al housing in the same manner as in the first embodiment with respect to the materials used and the process.

[Fourth Comparative Example]
In the fourth comparative example, in the seventh step (silicone rubber adhesive application process) in the first embodiment, the addition polymerization type silicone rubber adhesive 4 was applied to both ends of the UV curable adhesive 3 in an amount of 1.0 mg each. . Other than this, the collimator lens was fixed to the Al housing in the same manner as in the first embodiment with respect to the materials used and the process.

[Fifth Comparative Example]
In the fifth comparative example, the seventh step (silicone rubber adhesive application process) and the eighth step (silicone rubber adhesive thermal curing process) in the first example were not performed. Other than this, the collimator lens was fixed to the Al housing in the same manner as in the first embodiment with respect to the materials used and the process.

[Evaluation of Coverage of Addition Polymerization Type Silicone Rubber Adhesive 4]
Next, the method of measuring the values used to evaluate the coverage of the addition polymerization type silicone rubber adhesive 4 in the first and second examples and the first to fifth comparative examples will be described.

In the already explained sixth step (optical component/metal case fixing release process), after releasing the grip of the optical lens 1 (collimator lens), using a microscope (VHK5000 (manufactured by Keyence Corporation)), The surface area of the UV curable adhesive 3 that does not include the part to be adhered is measured. Let this measurement result be a "1st surface area."

Subsequently, after the eighth step (thermal curing of the silicone rubber adhesive), the surface of the addition polymerization type silicone rubber adhesive 4 that does not include the part to be adhered is observed, and the part where the UV curable adhesive 3 is exposed is observed. Measure the surface area. Let this measurement result be a "second surface area."

Subsequently, the coverage of the addition polymerization type silicone rubber adhesive 4 was calculated using the following formula (6). The calculated values are tabulated in FIG.

Formula (6)
Coverage [%] = 100 × (first surface area - second surface area) / first surface area

[Each test condition]
Using the optical lens structures 10 produced in the first and second examples and the first to fifth comparative examples, each environment (105 ° C., 85 ° C. 85%, temperature cycle (-40 C. to +105.degree. C.)). Here, the test method for each environment will be described.

(105°C environmental test)
The produced optical lens structure 10 was allowed to stand in a blower constant temperature thermostat (DKN402 (manufactured by Yamato Scientific Co., Ltd.)) and left at 105° C. for 1000 hours.

(85°C 85% environmental test)
The produced optical lens structure 10 was placed in a low-humidity (low temperature) thermo-hygrostat (PDL-4J (manufactured by Espec Co., Ltd.)) and left at 85° C. 85% for 1000 hours.

(Temperature cycle environmental test)
The produced optical lens structure 10 is left still in a thermal shock tester (TSA-72ES-A (manufactured by Espec Co., Ltd.)), and the temperature is changed from "-40 ° C. 30 minutes" to "+105 ° C. 30 minutes" and "+105 ° C. 1000 temperature cycles from "-40°C for 30 minutes" to "-40°C for 30 minutes" were performed.

(Position deviation evaluation)
A microscope (VHX-5000, Keyence, 200x magnification) was used to measure the displacement. An image of the bond is acquired with a microscope before each test (high temperature, high temperature humidity, temperature cycle). Then, one characteristic point was set by scratching the optical lens 1 (collimator lens) in advance and one characteristic point was set for the metal part (Al housing). Then, the normal direction of the collimator lens bonding surface of the line connecting the collimator lens characteristic point and the aluminum housing characteristic point was measured.

The normal direction of the collimator lens bonding surface of the line connecting the collimator lens characteristic point and the Al housing characteristic point means the "film thickness direction FL" shown in FIG. In the evaluation of positional deviation, the direction of the arrow in the film thickness direction FL shown in FIG. 8 is the positive direction.

Next, after each test (high-temperature exposure, high-temperature high-humidity, temperature cycle), an image of the adhesive part is acquired, and the normal direction of the collimator lens adhesive surface of the line connecting the collimator lens characteristic point and the Al housing characteristic point The value (film thickness direction FL) is measured, and the amount of change from before each test (high temperature, high temperature and high humidity, temperature cycle) is set as the amount of misalignment.

(Position deviation evaluation result)
FIG. 9 shows the positional deviation evaluation results after each test (high temperature, high temperature and high humidity, temperature cycle) described above. If the displacement over time is ±1% or less of the adhesive layer thickness of 200 μm, that is, ±200 μm or less, “◯” is entered in the judgment column, and if it is more than that, “×” is entered in the judgment column.

In FIG. 9, "A" written in the "adhesive type" column means an acrylic UV curable adhesive 3 that simultaneously satisfies the first and second requirements. Similarly, "B" written in the "adhesive type" column means the thermosetting addition polymerization type silicone rubber adhesive 4 that satisfies the third requirement.

As shown in FIG. 9, in the first embodiment and the second embodiment, the coverage of the addition polymerization type silicone rubber adhesive 4 is 100% and 50%, respectively. When the coverage is 50% or more, the activated oxygen radicals are absorbed or consumed by the addition polymerization type silicone rubber adhesive 4 and do not reach the UV curable adhesive 3 . Therefore, since oxygen does not come into direct contact with the UV curable adhesive 3 in an environment of 105° C., volatilization and oxidative decomposition of the initiator and additives of the UV curable adhesive 3 can be prevented. can prevent shrinkage due to Therefore, it is possible to suppress positional deviation over time in a 105° C. environment.

In the first comparative example, the UV curable adhesive 3 had a water absorption of 1.5% and a Tg of 90° C., which did not meet the first and second requirements. Since the water absorption rate is 0.5% or more, the positional displacement increases over time due to water absorption swelling of the UV curable adhesive 3 in an environment of 85° C. and 85%. In addition, since the Tg is 105° C. or less, in a 105° C. environment and a temperature cycle environment, the softening of the UV curable adhesive 3 causes compression deformation due to internal stress, resulting in displacement over time. Occur.

In the second comparative example, the heat loss of the addition polymerization type silicone rubber adhesive 4 was 1.2%, which did not satisfy the third requirement. Since the weight loss on heating in an environment of 105° C. is 0.5% or more, shrinkage due to the weight loss on heating of the addition polymerization type silicone rubber adhesive 4 causes an increase in displacement over time in the compression direction of the thickness of the adhesive layer.

In the third to fifth comparative examples, the coverage of the addition polymerization type silicone rubber adhesive 4 is less than 50%. If the coverage is less than 50%, the activated oxygen radicals cannot be absorbed or consumed by the addition polymerization type silicone rubber adhesive 4 in a 105° C. environment, and the oxygen comes into direct contact with the UV curable adhesive 3 . Therefore, in a 105° C. environment, volatilization and oxidative decomposition of the initiator and additives of the UV curable adhesive 3 occur, the UV curable adhesive 3 shrinks due to heat loss, and displacement occurs over time. When the coverage is less than 50%, the smaller the coverage of the addition polymerization type silicone rubber adhesive 4, the greater the heat loss of the UV curable adhesive 3, and the greater the displacement over time in the compression direction of the adhesive layer thickness.

As described above, according to the optical lens structure 10 according to the present embodiment, an adhesive is used to bond the optical components. A UV curable adhesive 3 that satisfies the requirements is placed. Then, 50% or more of the surface of the UV curable adhesive 3 that does not include the part to be adhered is covered with the addition polymerization silicone rubber adhesive 4 that satisfies the third requirement.

With such structural features, the silicone rubber of the optical lens structure 10 according to the present embodiment is less likely to be attacked by activated oxygen radicals. By covering 50% or more of the UV curable adhesive 3 with the addition polymerization type silicone rubber adhesive 4, the activated oxygen radicals are adsorbed or consumed by the addition polymerization type silicone rubber adhesive 4, resulting in the UV curable adhesive. Oxygen radicals do not reach the adhesive 3 .

Due to this action, oxygen does not come into direct contact with the UV curable adhesive 3 even in an environment of 105° C. for a long period of time. As a result, volatilization and oxidative decomposition of the initiator and additives of the UV curable adhesive 3 can be prevented, and shrinkage due to heat loss of the UV curable adhesive 3 can be prevented. As described above, according to the optical lens structure 10 according to the present embodiment, it is possible to suppress positional deviation over time in the usage environment (high temperature, high temperature and high humidity, temperature cycle).

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical scope of the invention. All matters are covered by the present invention. Although the above embodiment shows a preferred example, a person skilled in the art can realize various modifications from the disclosed contents. Such modifications are also included in the technical scope described in the claims.

1: Optical lens 2: Metal housing 3: UV curable adhesive 4: Addition polymerization type silicone rubber adhesive 10: Optical lens structure 100: Head-up display device 200: Optical component bonding device 210: Holder 211: Third One chuck tool 212: Second chuck tool 220: Adhesive applicator 230: Ultraviolet irradiation tool

JP-A-05-210851

Claims (2)

An optical component having an adhesive structure in which an optical lens and a metal housing are adhered and fixed by a UV curable adhesive containing 50% by mass or more of a filler made of a metal oxide and at least one or more types of adhesive. There is
The adhesive portion is
A UV curable adhesive that satisfies the following first and second requirements is placed in the center,
An optical component characterized by covering 50% or more of the surface of said UV curable adhesive, not including a part to be adhered, with an addition polymerization silicone rubber adhesive that satisfies the following third requirement.
1st requirement: 0.5% or less water absorption in 85°C 85% environment 2nd requirement: Tg 105°C or higher 3rd requirement: 0.3% or less heating loss in 105°C environment An optical component mounting device for mounting an optical component,
The storage temperature range is an environment that satisfies the following first, second and third conditions,
An optical component mounting apparatus, wherein the optical component is the optical component according to claim 1 .
First condition: 105° C. or less Second condition: The storage temperature range of the optical component mounting device is −40° C. to +105° C., and the device is stored in a temperature cycle environment within the storage temperature range.
Third condition: The temperature in the storage environment of the optical component mounting device is 85° C. or higher, and the humidity is 85% or higher.

Images