KR100698567B1 - Illuminator - Google Patents

Abstract

An object of the present invention is to realize a light source device capable of irradiating uniform inspection light to a central portion and a peripheral portion of a solid state imaging element.

This invention adds the improvement to the light source device used for the test | inspection of a solid-state image sensor. The apparatus includes a light generating section for outputting light, a lens section for injecting light from the light generating section, and irradiating light onto the solid-state image sensor, and a shorter focal length between the lens section and the light generating section. And an aperture stop arranged at a desired position.

Solid-state image sensor, light generation unit, aperture stop, lens unit, charge coupled device

Description

Light source device {ILLUMINATOR}

1 is a view showing the configuration of a conventional light source device.

FIG. 2 is a diagram showing a specific configuration of the lens portion 7 of the apparatus shown in FIG. 1.

3 is a view showing the illuminance ratio of the apparatus shown in FIG.

4 is a block diagram showing an embodiment of the present invention.

5 is a view for explaining the operation of the apparatus shown in FIG.

6 is a diagram showing the illuminance ratio of the apparatus shown in FIG. 4.

7 is a diagram illustrating a schematic configuration of a digital camera.

8 is a configuration diagram showing a second embodiment of the present invention.

9 is a view showing the operation of the apparatus shown in FIG.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a light source device used for inspection of solid-state imaging elements such as, for example, a CCD sensor and a CMOS sensor, and relates to a light source device capable of irradiating uniform inspection light to a central portion and a peripheral portion of the solid-state imaging element. .

Conventionally, in the inspection of solid-state imaging devices such as a charge coupled device (CCD) sensor and a complementary metal oxide semiconductor (CMOS) sensor, a light source device is used to inspect a solid-state imaging device to be inspected. The structure which irradiates the light of the color and the quantity of light, and monitors the electric signal output from the solid-state image sensor is used.

For example, it is shown to Unexamined-Japanese-Patent No. 2002-314054, and Unexamined-Japanese-Patent No. 2004-61154.

A description with reference to FIG. 1 is as follows. As shown in Fig. 1, the halogen lamp 1 outputs light. The lens 2 enters light from the halogen lamp 1 into a light beam that is approximately parallel light or slightly converges. The photosensitive opening 3 can control the opening area programmatically in an opening capable of mechanically shielding the light flux guided by the lens 2. In the ND (Neutral Density) filter unit 4, an ND filter 4b having different transmittances is disposed on a disk rotated by the motor 4a, and the light from the photosensitive opening 3 is transferred to the ND filter 4b. Pass it through. In the color filter part 5, the color filter 5b from which a color differs is arrange | positioned on the disk which rotates with the motor 5a, and the light from the ND filter part 4 passes the color filter 5b. The illuminance uniforming element 6 enters the light from the color filter part 5 from the incident surface, and irradiates from the emission surface with the light beam as approximately the same illuminance distribution. The lens portion 7 forms light from the illuminance equalization element 6. The CCD sensor 8 is irradiated with light from the lens portion 7 in the solid-state image sensor.

Next, the concrete structure of the lens part 7 is shown and demonstrated in FIG. As shown in Fig. 2, the lenses 7a and 7b are lenses called a zoom lens and a tablet back to the zoom lens, and the surfaces having the large curvature are aligned inward by combining the same focal lengths. The illuminance equalization element 6 (object surface) is disposed at the position of the optical axis image forming distance on the lens 7a side, and the CCD sensor 8 (the image is positioned at the position of the optical axis image forming distance on the lens 7b side). (像) is a side). The aperture stop 7c is provided between the lenses 7a and 8b, and the numerical aperture can be changed by changing the aperture diameter.

The operation of such a device is described below. Light of the halogen lamp 1 passes through the lens 2, the photosensitive opening part 3, the ND filter 4b of the ND filter part 4, and the color filter 5b of the color filter part 5, and illuminance. Incident on the homogenizing element 6. The illuminance uniforming element 6 equalizes illuminance, injects light into the lens portion 7, and injects light into the CCD sensor 8 from the lens portion 7. And the test of the CCD sensor 8 is performed by the IC tester which is not shown in figure.

The aperture diaphragm 7c between the lenses 7a and 7b is used to determine the light ray from the object plane (illumination equalization element 6) to the top surface (CCD sensor 8) that the angle α as the optical axis is the largest. As a member, the light rays emitted at an angle larger than this light beam are blocked by the stop 7c and do not reach the upper surface. Since the aperture stop 7c is located at the center of the symmetrical lens of the lenses 7a and 7b, coma aberration is canceled by the lenses 7a and 7b before and after the aperture. The distortion (distortion aberration) is changed by the position of the aperture stop 7c and canceled by being located at the center of the symmetrical lenses of the lenses 7a and 7b.

In such a device, coma aberration and distortion can be canceled, but the amount of ambient light is reduced by the cosine quadratic rule with respect to the angle of view β. 3 shows the simulation results by the optical design software. The horizontal axis represents the height and the vertical axis represents the roughness ratio. Although the amount of fall of the amount of ambient light differs with an image height, the fall of several%-about 10% is seen normally.

When such light is irradiated to the CCD sensor 8, since the quantity of light corresponding to a center part and a periphery part differs, accurate inspection was not able to be performed. Moreover, as the direction of the incident light obliquely changes toward the periphery of the CCD sensor 8, inspection conditions differ from the center part and the periphery part of the CCD sensor 8, and there existed a problem that an accurate inspection is not performed.

An object of the present invention is to realize a light source device capable of irradiating uniform inspection light to a central portion and a peripheral portion of a solid-state imaging element.

Hereinafter, the present invention will be described in detail with reference to the drawings. 4 is a block diagram illustrating main parts of an embodiment of the present invention. Here, the same components as those in Fig. 1 are given the same reference numerals and description thereof will be omitted.

As shown in FIG. 4, the lenses 9 and 10 are provided in place of the lens unit 7 and are lenses called a lens and a lens back to the lens. Make them face each other so that there is a little gap between them. The illuminance equalization element 6 (object surface) is disposed at the position of the optical axis image forming distance on the lens 9 side, and the CCD sensor 8 at a desired position shorter than the optical axis image forming distance on the lens 10 side. (Upper surface) is arranged. The aperture stop 11 is disposed between the lens 9 and the illuminance equalization element 6 at a desired position shorter than the combined focal length of the lenses 9 and 10, and the numerical aperture is changed by changing the aperture diameter. The composite focal length f is 1 / f = 1 / fa + 1 / fb-d / (fafb), fa: focal length of the lens 9, fb: focal length of the lens 10, d: lens ( 9, 10).

The operation of such a device is described below. Light of the halogen lamp 1 passes through the lens 2, the photosensitive opening part 3, the ND filter 4b of the ND filter part 4, and the color filter 5b of the color filter part 5, and equalize illuminance. It is incident on the element 6. The illuminance uniforming element 6 equalizes illuminance, irradiates light to the aperture stop 11, and the aperture stop 11 restricts the numerical aperture and emits light to the lenses 9 and 10. Then, the lens 10 emits light to the CCD sensor 8, and the test of the CCD sensor 8 is performed by an IC tester (not shown).

Here, the operation of the main part shown in Fig. 4 will be described in more detail. 5 is a view for explaining the operation of the apparatus shown in FIG. Here, the lenses 9 and 10 are briefly described as one lens. (a) is a case where the aperture stop 11 is disposed immediately after the lenses 9 and 10, and (b) is a case where the aperture stop 11 is arranged slightly on the object surface side from the lenses 9 and 10, (c) is a case where the aperture stop 11 is arrange | positioned at the position of the object surface side of the combined focal length of the lens 9,10.

In (a), the light emitted from the illuminance equalization element 6 reaches the CCD sensor 8 through the center of the lenses 9 and 10. (b) passes through the position where light (primary ray) from the illuminance equalization element 6 is slightly away from the center of the lens 9, 10 and the lens 9, 10, and reaches the CCD sensor 8. As shown in FIG. (c) is an upper telecentric optical system in which the light (primary rays) emitted from the illuminance equalization element 6 is parallel to the optical axis on the CCD sensor 8 side and becomes parallel rays on the image side. Here, the angles θ1 to θ3 of the chief ray on the CCD sensor 8 side and the optical axis become smaller as the aperture of the aperture stop 11 moves away from the lenses 9 and 10 and approaches the focal length position. However, with the telecentric optical system, the light beams are transmitted to the periphery very close to the lens, and the light beam diameter D3 is larger than the other light beam diameters D1 and D2. In the case of (c), the lenses 9 and 10 have a large diameter. We need to do with lens.

(C) That is, as a result of simulating the case of the telecentric optical system by optical software, it becomes as shown in FIG. As shown in FIG. 6, the horizontal axis represents image height, and the vertical axis represents roughness ratio. That is, the amount of ambient light increases by several percent to ten percent.

In such an apparatus, since the position of the aperture stop 11 is provided inside the combined focal position in front of the lenses 9 and 10, the main beam of the peripheral portion can be roughly parallel to the optical axis, so that the illuminance can be made uniform. Therefore, uniform inspection light can be irradiated to a fixed image pick-up element, and inspection can be performed with favorable precision. In addition, even if the diaphragm diameter is changed, the ambient light quantity ratio does not change, so that a desired F value is obtained while maintaining uniformity of illuminance.

The light from the lenses 9 and 10 is ideally formed in a plane perpendicular to the optical axis. However, the light is not necessarily formed in the plane and a clear image is reflected in the center, but the surroundings are blurred. However, if the position is shifted from the pin, the center becomes blurred and the surrounding image is synthesized. That is, since the positions of the lenses 9 and 10 are set to a desired position shorter than the imaging distance on the optical axis with respect to the CCD sensor 8, the center part is appropriately blurred so that the scratches and dusts on the minute surface of the illuminance uniformity element 6 are adhered. This can alleviate the dispersion of the illuminance distribution.

In addition, although the illuminance equalization element 6 tends to have high illuminance at the center portion and slightly decreases in the amount of ambient light, the illuminance can be corrected by adjusting the position of the aperture stop 11.

Next, a case of testing a CCD sensor with an on-chip microlens will be described. CCD sensors with on-chip microlenses are described in, for example, Japanese Patent Laid-Open No. 5-6986, Japanese Patent Laid-Open No. 6-125071, and the like. Hereinafter, the configuration of the digital camera will be described with reference to FIG.

As shown in FIG. 7, the CCD sensor 80 with the on-chip microlens is composed of a substrate 81, a photodiode 82, a vertical charge transfer line 83, and an on-chip microlens 84. A plurality of photodiodes 82 are formed on the substrate 81. Multiple vertical charge transfer lines 83 are formed between adjacent photodiodes 82. Many on-chip microlenses 84 are shifted with respect to the center of the CCD sensor 80 and are provided for each photodiode 82 to guide light to the photodiode 82. The lens 90 is installed above the CCD sensor 80 and guides light to the CCD sensor 80. The aperture diaphragm 100 is close to the lens 90, and adjusts the light from the lens 90 to the diaphragm and the CCD sensor 80.

In this way, in order to lower the position of the aperture stop 100 and to miniaturize the package, the pitch of the on-chip microlens 84 is configured toward the aperture stop 100. That is, in the photodiode 82 at point A, since the light is incident vertically, the on-chip microlens 83 is not shifted with respect to the photodiode, but in the photodiode 82 at the point B, light falling and incident on the photodiode 82 is detected. In consideration of this, shifting of the vignetting of the lens does not occur with the vertical charge transfer line 83, a light shielding film (not shown), a color filter, or the like.

The test operation of the CCD sensor 80 with such an on-chip microlens will be described with reference to FIG. 8. Here, the same reference numerals as those in Fig. 4 are assigned the same reference numerals and explanation thereof will be omitted. As shown in FIG. 8, the illumination region regulation pattern 12 is provided in proximity to the irradiation surface of the illuminance uniformity element 6, and regulates an illumination region. Instead of the CCD sensor 8, the inspection target is the CCD sensor 80.

The operation of such a device will be described. Light of the halogen lamp 1 passes through the lens 2, the photosensitive opening part 3, the ND filter 4b of the ND filter part 4, and the color filter 5b of the color filter part 5, and illuminance. Incident on the homogenizing element 6. The illuminance uniforming element 6 equalizes illuminance, the illumination region is regulated by the illumination region regulation pattern 12, and light is irradiated to the aperture stop 11. The aperture stop 11 restricts the numerical aperture and emits light to the lenses 9 and 10. The lens 10 emits light to the CCD sensor 80.

Generally, when inspecting the CCD sensor 80, the light emitted from the illuminance equalization element 6 is irradiated to the CCD sensor 80 through a pinhole, and light is irradiated obliquely to the peripheral part of the CCD sensor 80. I am trying to. However, as shown in a of FIG. 8, the amount of ambient light is small, which causes a great problem in inspection accuracy.

Therefore, since the position of the aperture stop 11 is provided inside the combined focal position in front of the lenses 9 and 10, as shown in FIG. 8B, the amount of ambient light is increased to illuminate the central portion and the peripheral portion. 5 can be made uniform and light can be inclined with respect to the peripheral part 8 of the CCD sensor 80 as shown in FIG. 8C illustrates a case in which the illumination region is restricted by the illumination region regulation pattern 12.

Moreover, in the inspection of the illumination by a pinhole, since the CCD sensor 80 is normally rectangular, it will become circular illumination of the diameter which covers a diagonal. That is, as shown in FIG. 9, when it becomes like illumination area | region L1, L2, and extra light is irradiated to the adjacent CCD sensor 80, and the same number of pinholes are opened with the same pitch as CCD sensor 80, Cone-shaped light is superimposed and the uniformity of illumination is impaired. Therefore, one CCD sensor 80 should be skipped and inspected. However, as shown in FIG. 9, after the illumination region is determined by the illumination region regulation pattern 12, the position of the aperture stop 11 is provided inside the combined focal length in front of the lenses 9 and 10. It becomes like illumination area | regions L3 and L4, and can apply light of uniform illumination to the adjacent CCD sensor 80. FIG.

As a result, for example, if the diameter of the falling light beam is 50 mm and the pitch of the CCD sensor 80 is 6 mm, the number of CCD sensors 80 that can be irradiated at the same time is 50 mm / 6 mm = 8 pieces. If one is skipped, it is half of four. That is, the test time can be shortened.

In addition, although this invention is not limited to this and the halogen lamp 1 was used as a light source, you may use a light emitting element.

Moreover, although the example of the lens part by two lenses of the lenses 9 and 10 was shown, you may comprise a lens part by one lens or some lens.

As apparent from the above description, the present invention has the following effects.

(1) Since the position of the aperture stop is provided inside the focal position in front of the lens portion, the illuminance can be made uniform. Therefore, uniform inspection light can be irradiated to a solid-state image sensor, and inspection can be performed with favorable precision. In addition, even if the diaphragm diameter is changed, the ambient light quantity ratio does not change, so that a desired F value is obtained while maintaining uniformity of illuminance.

(2) Since the position of the lens portion is a desired position shorter than the imaging distance on the optical axis with respect to the solid-state image pickup device, the center portion is appropriately blurred so that the disturbance in the illuminance distribution due to the scratches or adhesion of the minute surface of the light generating portion can be alleviated. .

(3) Although the illuminance equalization element tends to have higher illuminance in the center portion and slightly decrease the amount of ambient light, the illuminance can be corrected by adjusting the position of the aperture stop.

(4) The illumination region can be determined according to the illumination region regulation pattern, and light of uniform illuminance can be applied to the adjacent solid-state imaging element.

(5) Since the position of the aperture stop is provided inside the focal position in front of the lens portion, the amount of ambient light can be increased to uniform the illuminance of the center portion and the peripheral portion, and the light can be inclined with respect to the peripheral portion. The solid-state imaging device of the chip microlens portion can be tested.

Claims (5)

In the light source device used for the inspection of a solid-state image sensor, A light generating unit for outputting light; A lens unit for irradiating the solid state imaging element with light incident from the light generating unit; An aperture stop disposed at a desired position between the lens portion and the light generation portion, which is shorter than a focal length of the lens portion; Light source device comprising a. The method of claim 1, And the lens portion is disposed at a desired position shorter than the imaging distance on the optical axis with respect to the solid-state imaging element. The method according to claim 1 or 2, The light generation unit is an illuminance equalization element that uniformly illuminates the incident light and outputs the incident light. The method according to claim 1 or 2, A light source device comprising an illumination region regulation pattern provided in proximity to an exit surface of the light generation unit. The method according to claim 1 or 2, The solid-state imaging device is a light source device, characterized in that the on-chip micro lens attached.

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