JPH07168019A - Polarizing beam splitter and optical device - Google Patents

Abstract

PURPOSE:To relieve stresses to prevent peeling and cracking of films and to prevent the wavelength band of incoming beams from broadening by stacking a specific multilayer film on a substrate. CONSTITUTION:A multilayer film 8 comprising a first matching layer 4, a first stack group 5, a second stack group 6 and a second matching layer 7 is stacked on a substrate 3. The stacks constituting the multilayer film 8 are divided into at least two groups, the first stack group 5 comprising a plurality of material layers that are exerted with stresses in different directions, the second stack group 6 comprising a plurality of material layers that are exerted with stresses in the same direction and have a greater difference in refractive index between them than between two of the materials constituting the first stack group 5. For example, the multilayer film 8 comprises the first stack group 5 having a material layer 5a composed chiefly of TiO2 and a material layer 5b composed chiefly of SiO2 which are stacked alternately and the second stack group 6 having a material layer 6a composed chiefly of TiO2 and a material layer 6b composed chiefly of MgF2 which are stacked alternately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization beam splitter provided in the optical path of an optical system and an optical device using the same, and more particularly to a polarization beam splitter and an optical system capable of widening the wavelength band of incident light. Regarding the device.

[0002]

2. Description of the Related Art A conventional polarizing beam splitter has a multilayer film in which a material layer containing Si oxide as a main component and a material layer containing Ti oxide as a main component are alternately laminated on a substrate. It was composed by being deposited.

[0003]

In the polarization beam splitter as described above, in order to widen the wavelength band of the incident light, the difference in the refractive index between the two kinds of laminated material layers must be increased. . However, TiO ₂ and S
The difference in refractive index from iO ₂ is small. In order to increase this difference in refractive index, two types of material layers are used, TiO ₂ and M, respectively.
It may be composed of gF ₂ , but TiO ₂ and M
With gF ₂ , the stress generated in the film during film formation is in the same direction. Therefore, if the number of layers is increased, the stress in one direction increases, there is a risk that the film may peel off or cracks occur, and there is a problem that the number of layers is limited.

The present invention has been made in view of the above circumstances, and it is possible to prevent a peeling or a crack from occurring in the laminated material layers and to broaden the wavelength band of incident light. It is an object to provide a splitter and an optical device.

[0005]

In order to achieve the above object, the polarization beam splitter according to claim 1 has at least one multilayer film 8 in which at least two kinds of material layers are repeatedly laminated. In the polarization beam splitter 1 having a single substrate 3, the multilayer film 8 has at least two stacking groups, and the first stacking group 5 includes a plurality of material layers having different stress directions. It is characterized in that the stacking group 6 is composed of a plurality of material layers having the same stress direction and a difference in refractive index larger than a difference in refractive index between two kinds of materials constituting the first stacking group 5. And

The polarization beam splitter according to a second aspect of the invention is characterized in that the multilayer film 8 is composed of a plurality of material layers having different optical film thicknesses.

A polarization beam splitter according to a third aspect of the invention is characterized in that the number of boundaries between material layers having different stress directions is greater than the number of boundaries between material layers having the same stress direction.

In the polarization beam splitter according to the fourth aspect, the first stacking group 5 includes a material layer 5a containing Ti oxide as a main component and a material layer 5b containing Si oxide as a main component. The second stacking group 6 is made by repeatedly stacking Ti.
The material layer 6a containing the oxide as the main component and the material layer 6b containing the Mg fluoride as the main component are repeatedly laminated.

A polarization beam splitter according to a fifth aspect is arranged in a diverging or converging optical path of an optical system.

An optical device described in claim 6 is characterized by comprising a light receiving means for receiving the light transmitted or reflected by the polarization beam splitter 1 described in any one of claims 1 to 5.

An optical device according to a seventh aspect of the present invention is a light emitting means for emitting light to the object 102 to be detected (for example, L in FIG.
ED103) is provided.

An optical device according to an eighth aspect is characterized in that the presence or absence of the detected object 102 is detected based on the output of the light receiving means.

An optical device according to a ninth aspect is characterized in that the state of the detected object 102 is determined based on the output of the light receiving means.

[0014]

In the polarizing beam splitter having the above structure,
For example, the material layer 5a containing TiO ₂ as a main component and SiO ₂
And a material layer 6 containing TiO ₂ as a main component.
When a multilayer film 8 is formed by a second layer group 6 in which a and a material layer 6b containing MgF ₂ as a main component are alternately and repeatedly laminated, SiO ₂ and TiO ₂ are Since the directions are opposite, peeling or cracking is unlikely to occur even if the number of laminated layers is increased.

Further, since the difference in the refractive index between TiO ₂ and MgF ₂ is large, P in a wide wavelength band of incident light
The transmittance of the polarized component can be close to 100%, and the transmittance of the S polarized component can be close to 0%. That is, the band can be widened and the number of layers can be increased as compared with the case where the multilayer film 8 is composed of only TiO ₂ and SiO ₂ .

Further, by forming the multilayer film 8 with different optical film thicknesses, the degree of freedom in design is increased and a wider band can be realized. In particular, it is effective for widening the band when the incident angle has a range, such as in a convergent optical path or a divergent optical path.

The polarization beam splitter 1 having the above-described structure is provided with an LED 103 for emitting light to the object 102 to be detected,
The detection target object 102 is provided in an optical device provided with a light receiving unit that receives reflected, transmitted, and scattered light from the detection target object 102.
When the polarized beam splitter 1 separates the light from the P polarized light component and the S polarized light component, and the light receiving means receives the light to determine the presence or absence or the state of the detected object 102, the above-described characteristics of the polarized beam splitter 1 are used. The performance of the optical device can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the polarization beam splitter of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, the polarization beam splitter 1 is arranged in the optical path of the incident light 2 having S-polarized light and P-polarized light, so that the P-polarized light component is within the predetermined wavelength range of the incident light 2. Transmits almost 100%, transmits almost no S-polarized component, and reflects nearly 100%.

FIG. 1 shows the structure of a multilayer film according to the first embodiment of the present invention. The film thickness nd shown below has an optical film thickness of λ /
It is a multiple of four. A multi-layer film 8 including a first matching layer 4, a first stack group 5, a second stack group 6 and a second matching layer 7 is sequentially deposited on a substrate 3 having a refractive index n = 1.5. There is.

The matching layer 4 is TiO of nd = 0.94.
_The matching layer 7 is composed of _two layers 4a and a SiO ₂ layer 4b of nd = 0.55, and the matching layer 7 is made of SiO _{2 of} nd = 0.5.
It is composed of layers and has a function of removing the ripple characteristic appearing in the transmittance curve with respect to wavelength as shown in FIG. The first stack group 5 is composed of the TiO ₂ layers 5a of nd = 1 and nd.
= 1 and the SiO ₂ layers 5b are alternately laminated, 5 layers each. The second laminated group 6 is configured by alternately laminating four nd = 1 TiO ₂ layers 6a and four nd = 1 MgF ₂ layers 6b. Here, the refractive indexes of TiO ₂ , SiO ₂ , and MgF ₂ are 2.26, 1.46, and 1.39, respectively.

A method of designing a matching layer for removing ripples is well known, for example, H. H. et al. A.
It is disclosed in “Optical Thin Film”, Chapter 6 (published by Nikkan Kogyo Shimbun) by Macleod (1989).

In the polarization beam splitter 1 having the multilayer film 8 as described above, as shown in FIG. 1, the incident angle θ = 65 °.
Wavelength of incident light 2 when incident light 2 is incident at (nm)
3 is shown by a curve A in FIG. 3 for the transmittance Tp of the P-polarized component and the transmittance Ts of the S-polarized component. In addition, the curve B is a T of nd = 1 for all the laminated groups 5 and 6.
shows the characteristics when the multilayer film 8 constituting iO ₂ layers 5a and nd = 1 of the SiO ₂ layer 5b alternately stacked one by each nine layers.

According to this embodiment, T having a large difference in refractive index is used.
Since the second stacking group 6 in which the iO ₂ layer 6a and the MgF ₂ layer 6b are stacked is deposited, as shown in FIG.
Broadening of the band can be realized as compared with the case of only the first laminated group 5 in which the O ₂ layer 5a and the SiO ₂ layer 5b are laminated. In addition, the stress direction is opposite to that of the TiO ₂ layer 5a and SiO _2.
Since the first stacking group 5 in which the _two layers 5b are stacked is deposited, only the second stacking group 6 in which the TiO ₂ layer 6a and the MgF ₂ layer 6b, which have the same stress direction, are stacked. As compared with the above case, it is possible to prevent the peeling and cracking of the film due to the generation of stress during film formation.

In the second embodiment of the present invention, the first matching layer 4 shown in FIG. 1 is composed of a TiO ₂ layer 4a with nd = 1.13 and a SiO ₂ layer 4b with nd = 0.57. The laminated group 5 of No. 1 is constituted by alternately laminating five TiO ₂ layers 5a of nd = 0.95 and five SiO ₂ layers 5b of nd = 1.09. The second stack group 6 has nd = 1.0.
6 TiO ₂ layers 6a and nd = 0.92 MgF ₂ layers 6b are alternately laminated in four layers,
The matching layer 7 is composed of a SiO ₂ layer of nd = 2.10. That is, the degree of freedom in design is improved by shifting the film thickness of the material layers forming the stack groups 5 and 6 from λ / 4.

FIG. 4 shows the relationship between the wavelength of the incident light 2 and the transmittance in the multilayer film 8 according to the second embodiment. As shown in FIG. 4, the wavelength band of the incident light 2 can be broadened by this embodiment as well.

Further, the film thicknesses of the material layers constituting the laminated groups 5 and 6 are not the same for the same material layers, but all the film thicknesses are set to arbitrary values, thereby further increasing the degree of freedom in design. Can be improved. Such design optimization is achieved by sequentially changing the thickness of layers from the initial design using a computer and gradually improving the performance.

FIG. 5 shows the structure of a multilayer film according to the third embodiment of the present invention. In this example, a third matching layer 11 having the same structure as the first matching layer 4 was provided between the first laminated group 5 and the second laminated group 6 shown in FIG. According to this embodiment, the degree of freedom in design is improved and desired characteristics can be easily obtained.

FIG. 6 shows the configuration of the fourth embodiment of the present invention. In this embodiment, the polarization beam splitter 1 is arranged on the convergent optical path. In this case, the incident angles of incident light θ ₁ , θ ₂ , and θ ₃ are different. At this time, the matching layer is
As shown in FIG. 5, TiO ₂ is provided at three locations.
The number of boundaries between the layer 5a and the SiO ₂ layer 5b is made larger than the number of boundaries between the TiO ₂ layer 6a and the MgF ₂ layer 6b. Moreover, the degree of freedom in design is increased by displacing the film thickness of the material layers forming each of the stack groups 5 and 6 from λ / 4. Wavelength of incident light 2 (n
m), the relationship between the incident angle (θ) and the transmittance (%) is shown in FIG. 8, and the relationship when the material layer is composed of only the TiO ₂ layer and the SiO ₂ layer as in the conventional case is shown in FIG.

The characteristic curves shown in FIGS. 7 and 8 are calculated based on the example of the film structure shown below. Here, the design wavelength is 940 nm, and the film thickness nd of each layer laminated from the substrate side in order from the upper left is shown. (A) The film structure of FIG. 7 1.22 TiO ₂ -1.71 SiO ₂ -0.20 TiO _2-
(0.96SiO ₂ −0.97TiO ₂ ) × 5-1.07SiO
₂ -0.97TiO ₂ -1.12SiO ₂ - (0.96TiO
₂ -0.98SiO ₂₎ × 5-0.14TiO ₂ -1.71S
iO ₂ −0.88 TiO ₂ (b) Film structure of FIG. 8 1.99 TiO ₂ −1.07 SiO ₂ −0.49 TiO ₂ −
(0.92SiO ₂ −0.98TiO ₂ ) × 5-1.01SiO
₂ -0.97TiO ₂ -1.12SiO ₂ - (0.96TiO
₂ -0.99MgF ₂₎ × 5-1.88SiO ₂ -0.69T
iO ₂

According to this embodiment, the number of boundaries of the material layers forming the first stacking group 5 is made larger than the number of boundaries forming the second stacking group 6, so that the stress of the film formation causes the film formation. It is possible to prevent the occurrence of peeling and cracks, and it is possible to form multiple layers, which improves productivity. In addition, the present embodiment shown in FIG. 8 can realize a wider wavelength band of incident light than the conventional example shown in FIG.

In each of the above embodiments, the flat polarization beam splitter 1 has been described, but the same effect can be obtained by applying it to a polarization beam splitter having a prism shape or the like.

The number of laminated layers is not limited to two, and may be three or more. Further, the material layers forming each stacking group are not limited to the above-mentioned three types, and may be a combination of other materials as long as they have equivalent characteristics.

Although FIG. 6 shows the case where the polarization beam splitter 1 is arranged on the convergent optical path, the same effect can be obtained by arranging it on the divergent optical path.

Next, embodiments of the optical device of the present invention will be described with reference to the drawings.

FIG. 9 shows a first embodiment showing the basic concept of the optical device of the present invention. For example, L as a light emitting means for emitting light to the object 102 to be detected is provided in the housing 101.
The ED 103 is arranged, and the light emitted from the LED 103 is projected obliquely onto the detected object 102. The projection light emitted to the detected object 102 is reflected by the detected object 102 and is received by the light receiving means arranged inside the housing 101. The light receiving means includes a polarization beam splitter 1 which is one of the polarizers,
It is composed of first and second light receiving elements 104 and 105. The polarization beam splitter 1 has a parallel plate made of a transmissive glass material as a substrate, and the above-mentioned multilayer film 8 is formed on the incident side surface of the reflected light from the object to be detected 102, whereby the light is incident from an oblique direction. The reflected light is split into two lights having two polarization components that are orthogonal to each other. That is,
The S-polarized component is reflected on the surface of the polarization beam splitter 1 and projected on the first light receiving element 104. Also P
The polarized component is transmitted through a parallel plate base made of a transparent glass material and is projected on the second light receiving element 105.

In the above structure, when the detected object 102 is a transparent body, the reflectance of the S-polarized component on the detected object 102 is higher than the reflectance of the P-polarized component. Further, when the surface of the detected object 102 is a rough surface, the reflectances of the both polarization components are substantially equal. Therefore, by taking the ratio of the outputs from the two light receiving elements 104 and 105, it is possible to determine whether or not the detected object 102 is a transparent body, and the surface of the transparent body (glass) is fogged. In the case of water drops or when water drops adhere, the surface condition can be detected by the same principle.

At this time, even if the position of the object to be detected 102 is slightly changed or the inclination is slightly changed, the S-polarized light component and P which are incident on the two light receiving elements 104 and 105 and P
The light amount of the polarization component changes in the same manner, and the two light receiving elements 104
There is little variation in the ratio of the outputs of 105 and 105, thus ensuring stable detection.

FIG. 10 shows the configuration of the second embodiment of the present invention, which is an example of a transmission type detection device in which the light projecting portion and the light receiving portion are separated. The light emitted from the LED 103 is obliquely incident on and transmitted through the detected object 102,
Then, similarly to the first embodiment, the transmitted light is split into two light components having two polarization components orthogonal to each other.

In the above structure, when the detected object 102 is a transparent body, the transmittance of the P-polarized component in the detected object 102 is higher than the transmittance of the S-polarized component. Therefore,
By taking the ratio of the outputs from the two light receiving elements 104 and 105, it is possible to determine whether or not the detected object 102 is a transparent body, and if it is a transparent body having a different refractive index, P polarization Since the transmittance of the component and the transmittance of the S-polarized component change, it is possible to distinguish between the transparent bodies.

In addition, similarly to the first embodiment, even if a foreign matter adheres to the surface of the transparent body, the surface condition of the foreign matter can be detected.

FIG. 11 shows a third embodiment to which the second embodiment is applied, in which the semiconductor laser LD103a is used so as to mainly emit P-polarized light or S-polarized light from the light emitting section. Then, the light is received by the two light receiving elements 104 and 105 in the light receiving section.
When 2 does not exist, there is almost no output from one light receiving element that receives P or S polarized light, but an object 201 that scatters light in this optical path (compared to rain, snow, fog or beam diameter). If there is a small foreign matter or a transparent body having a rough surface, the outputs of the two light receiving elements 104 and 105 change, and the presence thereof can be detected.

FIG. 12 shows a fourth embodiment of the construction for detecting the surface condition. From the LED 103,
The LED light is emitted as polarized light through the polarizer 110. In this case, the LED 103 using a semiconductor laser,
The polarizer 110 may be removed. First from LED 103
The light near the optical axis of the light slightly diverged and emitted through the optical lens 112 is made to enter the object 102 to be detected substantially vertically. Then, the light receiving unit is arranged so that the specularly reflected light reflected by the detected object 102 can be converged and received via the second optical lens 113.

At this time, if the surface of the detected object 102 is flat, the polarization component of the light emitted from the LED 103 is stored and reflected, and if the surface is rough, it is diffusely reflected on the surface. For example, when the surface is completely rough without preserving the polarized light, the light receiving amounts of the two light receiving elements 104 and 105 are substantially the same. Therefore, it is possible to determine the surface state of the detected object 102.

The structure as shown in FIG.
When 02 does not exist, the light emitted from the LED 103 is reflected by the flat background or cylindrical background objects 91 and 92 as in the fifth embodiment shown in FIGS.
It is assumed that light is received by the optical device 93 having 04 and 105.

At this time, if the background objects 91 and 92 are made of metal, when the object 102 to be detected does not exist, the light receiving element 10
Since the polarization directions of the light from the LEDs 103 are stored and entered in the reference numerals 4, 105, the ratio of the two received light amounts is substantially the same. (Because the LED 103 emits randomly polarized light). Therefore, when the paper 94 or the like that is almost diffused and reflected as the detected object 102, the ratio of the two received light amounts becomes substantially the same, so that the distinction is lost and another calculation is required.

Therefore, as shown in FIG.
6, a dielectric 95 (for example, glass) is selected, or a paint 97 is applied to the metal 96 as shown in FIG. 15 to make the reflectances of the P-polarized component and the S-polarized component different. The detection described above can be detected by the same calculation.

Further, this apparatus moves on the object 102 to be detected and detects the edge of the object 102 to detect the object 1 to be detected.
When determining the size, posture, position shift, etc. of 02, the background 91, 92
If there is a change in the material or surface state of the object, accurate edge detection becomes impossible, and even if the detected object 102 is a transparent body, even the detection may become indistinguishable.

A procedure for automatically setting a threshold will be described as a fifth embodiment. When an automatic tuning command is issued or at a predetermined timing (for example, when the power is turned on or for a certain period of time), the threshold value is automatically adjusted or corrected in the following procedure.

In the first procedure, the sensing object to be discriminated is sensed by the user in a predetermined order, or the sensing device or a device equipped with the sensing device is sequentially sensed from the part stocked therein. The optimum threshold value is set based on the output signal of the device. In the second procedure, a limited object to be detected, which is relatively difficult to discriminate, is sensed in the same manner as in the first procedure, and an optimum threshold value is set from the output signal of the device.

The sixth embodiment shown in FIG. 17 shows an application example of the detection device. In the example shown in FIG. 17, in a printing machine such as a printer or a copy machine (other word processors, plotters, faxes, recorders, etc.), is the print target (detected object) 102 stored in the paper tray 102 paper, The example shown is used to detect whether it is an OHP film, that is, whether it is a transparent body or an opaque substance, or to detect the type of paper (plain paper, thermal paper, coated paper).

The detecting device A is arranged above the paper tray, discriminates an object to be printed, and adjusts and sets mechanical parameters of the conveying path, parameters such as a printing method and a printing density for the printing process.

In addition, this detection device
It may be arranged (not shown) in the conveyance path, the object to be printed may be discriminated, and the above-mentioned parameters may be adjusted and set.

FIG. 18 shows an example in which the detection device A of the present invention as the paper discriminating device is attached to the print head B to adjust the parameters of the printing process according to the type of paper to be printed. is there.

Since the printer is attached to the print head B, the size of the paper can be determined by detecting the edge of the paper.
Optimal printing is possible by detecting the posture and position shift.

The seventh embodiment shown in FIG. 19 shows another application example of the detection apparatus of the present invention. In the example shown in FIG. 19, the detection device A is arranged on the dashboard 40 of an automobile to detect the degree of fog on the windshield 41. That is, it is possible to detect the degree of fogging by detecting the presence or absence of gloss on the inside surface of the windshield 41, and when the amount of fog exceeds a predetermined level, the air conditioner is automatically operated. , Can be controlled to work the dehumidification function. In addition to cars, it can also be applied to the detection of fog on windows of homes and buildings, or on mirrors.

Further, as shown in FIG. 20, the detector A detects whether or not water droplets are attached to the surface of the windshield 41 (outside the vehicle body), and it is determined that water droplets of a predetermined amount or more are attached. In some cases, the wind wiper can be automatically controlled to operate.

It is also possible to detect a change in the intensity of light entering from the outside of the windshield 41 and control the light to be automatically turned on / off with a predetermined illuminance as a threshold value.

Furthermore, the eighth embodiment shown in FIG. 21 shows another application example of the detection apparatus of the present invention.
In the example shown in FIG. 21, the detection device A for detecting the surface state of the radiator 51 of the air conditioner outdoor unit 50 is arranged in the immediate vicinity of the radiator 51. That is, whether or not frost is attached to the surface of the radiator 51 is detected, and the operating state of the air conditioner outdoor unit 50 is automatically controlled.

Similarly, it can be applied to detecting the frost adhering to the radiator of the refrigerator and controlling the operating condition. As a ninth embodiment based on the same principle, for example, it is possible to provide a function of notifying the user by detecting dust on the fan, or a function of automatically removing dust. It is also possible to realize efficient operation by detecting a clogging caused by dust in the filter inside the machine and providing a function for notifying the user.

As a tenth embodiment, the same principle applies to a foreign matter inspection apparatus on a manufacturing line, that is, when polarized light is emitted from the LED 103 and no foreign matter is present on the object with the configuration shown in FIG. The polarized light is preserved and is received by the light receiving elements 104 and 105. However, if a foreign substance is present on the object, diffuse reflection occurs, so that the polarization is spilled and the output from the light receiving elements 104 and 105 changes. Foreign matter can be detected. Based on such a principle, it is possible to improve the function by attaching the detection device to a device used in a semiconductor manufacturing process such as a mask aligner.

In the eleventh embodiment shown in FIG. 22, the detection device A detects the road surface condition to perform the optimum control of the ABS (anti-lock brake system) and the suspension, the hardness of the brake, the steering wheel or the accelerator. , Is an example of adjusting the transmission condition.

This is the principle opposite to that of the tenth embodiment. In the structure shown in FIG. 9, polarized light is reflected and reflected on an ordinary road surface, but when the road surface is wet, the polarized light is preserved and reflected. Is detected. By this, a safer vehicle (control) can be realized.

As another application, by attaching this device to the end of the car (around the bottom of the door), the center line is detected, and when the car is running out of the center line due to sleep etc. It has a function to inform people and realizes safe driving.

23 and 2 will be described as a twelfth embodiment utilizing the fact that a transparent body can be detected by the structure shown in FIG.
As shown in FIG. 4, it is applied to detect the presence or absence of the transparent sheet or the transparent film D in the production line C, or the transparent film packaged in the product.

In the detection device of the present invention, for example, by configuring as shown in FIG. 9, it is possible to determine the type of the dielectric material based on the difference in the refractive index and the surface state. It is possible.

Therefore, as a thirteenth embodiment, an application example as a color mark sensor, a color copying machine having a color check function, or an inspection machine for a coating apparatus can be considered.

As a fourteenth embodiment to which the inspection apparatus of the present invention is capable of discriminating the quality of paper and the quality of ink, discrimination of banknotes by a CD, ATM vending machine or the like, particularly discrimination of fake bills is carried out. Conceivable.

FIG. 25 shows the bill insertion slot F of such an apparatus E.
In this example, the detection device A of the present invention is arranged and bill discrimination is performed.

The fifteenth embodiment shown in FIG. 26 is an application example as an apparatus for measuring the film thickness of a liquid. In the configuration as shown in FIG. 9, if the LED 103 emits light to the rough surface and the light receiving elements 104 and 105 receive the specular reflection light and the diffuse reflection light, the thickness of the liquid G causes Since the ratio of receiving the specular reflection light and the diffuse reflection light changes, the film thickness is detected by changing the amount of light received by the two light receiving elements. Thereby, for example, in offset printing, it can be used as a device for keeping the thickness of the dampening water adhered constant, and beautiful printing can be realized.

[0071]

As described above, according to the polarization beam splitter of the present invention, a laminated group composed of a plurality of material layers having different stress directions generated during film formation and a plurality of materials having a large difference in refractive index. A polarizing beam splitter was formed by depositing a multi-layered film consisting of a stack of layers on the substrate, so stress is relieved and film peeling and cracking are prevented even if the number of stacked layers is increased. it can. Further, the degree of freedom in design is increased, and the wavelength band of incident light can be broadened.

Further, since the polarization beam splitter having the above-mentioned configuration is provided in the optical device, the light emitted from the light emitting means is irradiated to the object to be detected, and the reflected light or the transmitted light is received by the light receiving means. It is possible to efficiently determine the presence or the state of an object.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a first embodiment of a polarization beam splitter of the present invention.

FIG. 2 is an explanatory diagram showing an example of the arrangement of a polarization beam splitter in the optical path.

FIG. 3 is a diagram showing optical characteristics of the polarization beam splitter shown in FIG.

FIG. 4 is a diagram showing optical characteristics of a second embodiment of the polarization beam splitter of the present invention.

FIG. 5 is a vertical sectional view showing the configuration of a third embodiment of the polarization beam splitter of the present invention.

FIG. 6 is an explanatory diagram showing an arrangement in a converging optical path of a polarization beam splitter according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing optical characteristics of an example of a conventional polarization beam splitter arranged in a convergent optical path.

8 is a diagram showing optical characteristics of the polarization beam splitter shown in FIG.

FIG. 9 is a side view showing the basic structure of the optical device according to the first embodiment of the present invention.

FIG. 10 is a side view showing the configuration of the second exemplary embodiment of the present invention.

FIG. 11 is a side view showing the configuration of the third exemplary embodiment of the present invention.

FIG. 12 is a side view showing a basic configuration of a fourth exemplary embodiment of the present invention.

FIG. 13 is a perspective view showing an arrangement according to a fifth example of an example of a background object provided in the optical device of the present invention.

FIG. 14 is a perspective view showing the arrangement of another example of the background object provided in the optical device of the present invention.

FIG. 15 is a side view showing an example of an improved configuration of the background object shown in FIG.

16 is a perspective view showing another example of the improved configuration of the background object shown in FIG.

FIG. 17 is a perspective view showing an application example of a sixth embodiment of the optical device of the present invention.

FIG. 18 is a perspective view showing another application example of the sixth embodiment of the optical device of the present invention.

FIG. 19 is a perspective view showing an application example of a seventh embodiment of the optical device of the present invention.

FIG. 20 is a side view showing another application example of the optical device according to the seventh embodiment of the present invention.

FIG. 21 is a perspective view showing an application example of an optical device according to an eighth embodiment of the present invention.

FIG. 22 is a perspective view showing an application example of an optical device according to an eleventh embodiment of the present invention.

FIG. 23 is a perspective view showing an application example of a twelfth embodiment of the optical device of the present invention.

FIG. 24 is a perspective view showing another application example of the twelfth embodiment of the optical device of the present invention.

FIG. 25 is a perspective view showing an application example of a fourteenth embodiment of the optical device of the present invention.

FIG. 26 is a side view showing an application example of the optical device according to the fifteenth embodiment of the present invention.

[Explanation of symbols]

 1 Polarization Beam Splitter 3 Substrate 5, 6 Lamination Group 8 Multilayer Film 102 Detected Object 103 LED (Light Emitting Means)

Claims (9)

[Claims] 1. A polarizing beam splitter having at least one substrate on which a multi-layered film formed by repeatedly stacking at least two kinds of material layers is deposited, wherein the multi-layered film comprises at least two stacking groups, The first laminated group is composed of a plurality of material layers having different stress directions, and the second laminated group is composed of two materials having the same stress direction and a difference in refractive index among the materials composing the first laminated group. A polarization beam splitter comprising a plurality of material layers having a larger refractive index difference between seed materials. 2. The polarization beam splitter according to claim 1, wherein the stack group is composed of a plurality of material layers having different optical film thicknesses. 3. The polarization beam splitter according to claim 1, wherein the number of boundaries between material layers having different stress directions is greater than the number of boundaries between material layers having the same stress direction. 4. The first stacking group is formed by repeatedly stacking a material layer containing Ti oxide as a main component and a material layer containing Si oxide as a main component. The polarization beam splitter according to claim 1, wherein the stacking group is formed by repeatedly stacking a material layer containing Ti oxide as a main component and a material layer containing Mg fluoride as a main component. . 5. The polarizing beam splitter according to claim 1, wherein the polarizing beam splitter is arranged in a diverging or converging optical path of an optical system. 6. An optical device comprising a light receiving means for receiving light transmitted or reflected by the polarization beam splitter according to claim 1. Description: 7. The optical device according to claim 6, further comprising a light emitting unit that emits light to the object to be detected. 8. The optical device according to claim 6, wherein the presence or absence of the detected object is detected based on the output of the light receiving unit. 9. The optical device according to claim 6, wherein the state of the detected object is determined based on the output of the light receiving unit.