JP-7855865-B2 - Inspection device and inspection method

JP7855865B2JP 7855865 B2JP7855865 B2JP 7855865B2JP-7855865-B2

Inventors

長谷川栄
吉岡英範
稲月友一
林謙太

Assignees

大日本印刷株式会社

Dates

Publication Date: 20260511
Application Date: 20220204

Claims (4)

An inspection device for inspecting a diffractive optical element sheet in which multiple unit diffractive optical elements are arranged within the sheet surface, A holding portion for holding the diffractive optical element sheet, The diffractive optical element sheet held in the holding part is provided with a light-emitting unit that emits inspection light, A camera unit for capturing the inspection light that has passed through the diffractive optical element sheet, The system includes a control unit that acquires an image of the diffractive optical element sheet from the imaging unit and inspects each unit diffractive optical element based on the image, The imaging unit outputs the brightness of each unit diffracting optical element, The control unit corrects the brightness value for each unit diffracting optical element by multiplying the brightness value by a correction coefficient corresponding to the diffraction angle of the inspection light incident on the unit diffracting optical element. The aforementioned correction coefficient is calculated by the correlation between the integrating sphere intensity and brightness value of the measured data in the inspection device.
The correction coefficient is calculated using the following formula: Correction factor = 1 / (cosθ)p (θ is the diffraction angle of the inspection light L incident on each spot of the unit diffracting optical element, and p is the cosθ power coefficient, which takes the same value for all spots.) The inspection apparatus according to claim 1, as defined by [the relevant law].
An inspection method for inspecting a diffractive optical element sheet in which multiple unit diffractive optical elements are arranged within the sheet surface, The step of holding the diffractive optical element sheet, The process involves projecting inspection light onto the held diffractive optical element sheet, A step of capturing the inspection light that has passed through the diffractive optical element sheet, The process includes acquiring an image of the diffractive optical element sheet that has been photographed, and inspecting each unit diffractive optical element based on the image, In the process of capturing the inspection light, the brightness of each unit diffracting optical element is output, Beforehand, we measured the actual data using an integrating sphere. A correction coefficient is determined by the correlation between the integrating sphere intensity and brightness value of the measured data. An inspection method comprising the step of inspecting each of the aforementioned unit diffractive optical elements, wherein for each unit diffractive optical element, the value of the brightness is corrected by multiplying the value of the brightness by a correction coefficient corresponding to the diffraction angle of the inspection light incident on the unit diffractive optical element.
The correction coefficient is calculated using the following formula: Correction factor = 1 / (cosθ)p (θ is the diffraction angle of the inspection light L incident on each spot of the unit diffracting optical element, and p is the cosθ power coefficient, which takes the same value for all spots.) The inspection method according to claim 3, as defined by [the relevant law].

Description

This disclosure relates to an inspection device and an inspection method. Diffractive optical elements have been known for some time. Diffractive optical elements are also called DOEs. Diffractive optical elements are optical elements that shape the light from a light source of various sensors to match the size and shape of the target illumination area. Diffractive optical elements are devices that utilize the diffraction phenomenon. Diffraction is a phenomenon that occurs when light passes through a region where materials with different refractive indices are arranged in a periodic manner. Diffractive optical elements are basically designed for light of a single wavelength. Theoretically, diffractive optical elements can shape light into any desired form. Diffractive optical elements can control the uniformity of the light distribution within the illuminated area. Diffractive optical elements are manufactured by microfabrication on the nanometer scale. In particular, to diffract long-wavelength light, it is necessary to form fine shapes with a high aspect ratio. Therefore, electron beam lithography is used in the manufacture of diffractive optical elements. To improve productivity, multiple duplicate substrates may be produced by molding a substrate such as quartz, created by electron beam lithography, into resin. By mounting multiple optical elements, such as diffractive optical elements, onto a single substrate, a large number of optical elements can be manufactured from a single substrate. These mounted optical elements are then separated into individual pieces using methods such as dicing and punching, and mounted onto electronic components such as holders. As mentioned above, diffractive optical elements shape light through their minute shapes, so even slight changes in shape can easily lead to significant changes in their optical properties. Therefore, for diffractive optical elements used in sensors and other applications requiring particularly high detection accuracy, it is desirable to inspect whether the optical properties are appropriate after manufacturing. International Publication No. 216575 (2018/216575) Figure 1 is a schematic plan view showing an inspection device according to one embodiment.Figure 2 is a front view showing the holder and the diffractive optical element sheet.Figure 3 is a schematic cross-sectional view showing a part of an inspection device according to one embodiment, along the optical path of the inspection light.Figure 4 shows an image captured by photographing the inspection light that has passed through the chip.Figures 5(a)-5(c) show an inspection method according to one embodiment.Figure 6 is a graph showing the results of measuring the intensity of the inspection light incident on the chip using an integrating sphere.Figure 7(a) is a graph showing the measured brightness values for each spot on the chip, and Figure 7(b) is a graph showing the corrected brightness values for each spot on the chip. The following description of one embodiment will be given with reference to Figures 1 to 7. Note that in the following figures, the same parts are denoted by the same reference numerals, and some detailed explanations may be omitted. Figure 1 is a schematic plan view showing the inspection apparatus according to this embodiment. Note that all figures shown below, including Figure 1, are schematic representations, and the size and shape of each part are exaggerated as appropriate for ease of understanding. Furthermore, while specific numerical values, shapes, materials, etc., are shown in the following description, these can be changed as appropriate. In this specification, terms that specify shapes and geometric conditions, such as parallel and orthogonal, include not only their strict meaning but also states that exhibit similar optical functions and have an error that can be considered parallel or orthogonal. In this specification, terms such as plate, sheet, and film are used. These are generally used in the order of plate, sheet, and film, in order of increasing thickness, and this specification follows that convention. There is no technical significance to this distinction, and these terms can be replaced as appropriate. In this specification, the sheet surface refers to the surface of each sheet that aligns with the planar direction when viewed as a whole. The same applies to the plate surface and film surface. Also, in this specification, transparent means that it transmits at least the wavelength of light to be used. For example, even if a material does not transmit visible light, if it transmits infrared light, it will be treated as transparent when used for infrared applications. As shown in Figure 1, the inspection apparatus 10 according to this embodiment is an apparatus for inspecting a diffractive optical element sheet 80 in which a plurality of unit diffractive optical elements are arranged within the sheet surface. In this embodiment, the case in which the