KR20200061807A - Apparatus for measuring contrast ratio of image sensor and method for measuring the same - Google Patents

Abstract

The present invention relates to an image sensor contrast ratio measurement device for improving the accuracy and reproducibility of contrast ratio measurement and a measurement method thereof. According to an embodiment of the present invention, the image sensor contrast ratio measurement device comprises: a compressed air injection bar; a signal injection contact block; a front contact block guide; a square support part; a vertical support column; a sensor support block; a digital current display part; an analog current display part; a power switch; up and down operation buttons; a signal injection wire; and a measurement image display part.

Description

Image sensor contrast ratio measuring device and measuring method thereof

An image sensor contrast ratio measuring apparatus and a measuring method thereof are provided.

In an image (for example, a fingerprint image) generated by a capacitive image sensor (for example, a fingerprint recognition sensor), a portion of the sensor surface corresponding to an object (for example, a finger) that touches a portion is displayed relatively brightly. , The part that the subject does not touch is displayed relatively dark. The higher the contrast ratio of the generated image, the sharper the image. Therefore, in evaluating the performance of the capacitive image sensor, the contrast ratio is an important factor.

In order to measure the contrast ratio of the capacitive image sensor, the conventional image sensor contrast ratio measuring apparatus measures the contrast ratio after dropping water droplets on the sensor surface. However, the method of measuring by dropping water droplets may take a long time, and the results may vary depending on the specific actions of the user using the device, such as the size of the water droplets being changed. Since the contact angle of the droplet or the contact area of the droplet with respect to the sensor surface may vary, the accuracy of the measurement result may deteriorate. In addition, it is not easy to completely recover water droplets after measurement, and residual moisture remaining on the sensor surface may degrade sensor performance.

The contrast ratio measuring apparatus of the image sensor and the measuring method thereof according to an embodiment of the present invention are for improving the accuracy and reproducibility of contrast ratio measurement.

The contrast ratio measuring apparatus of the image sensor and the measuring method thereof according to an embodiment of the present invention are for deriving a uniform measurement result even when there are changes in environment or conditions.

In addition to the above problems, embodiments according to the present invention can be used to achieve other problems not specifically mentioned.

Image sensor contrast ratio measuring apparatus according to an embodiment of the present invention, compressed air injection bar, signal injection contact block, front contact block guide, square support, vertical support column, sensor support block, digital current display, analog current display, power switch , Up and down operation buttons, signal injection wire, and measurement image display.

The contrast ratio measuring apparatus of the image sensor and its measuring method according to the embodiment of the present invention can improve the accuracy and reproducibility of the contrast ratio measurement, and the contrast ratio measuring apparatus of the image sensor and the measuring method of the image sensor according to the embodiment of the invention Even if there are changes in conditions, uniform measurement results can be obtained.

1 is a photograph showing an image sensor contrast ratio measuring apparatus according to an embodiment.
FIG. 2 is an enlarged photograph of a signal injection contact block of the image sensor contrast ratio measuring apparatus of FIG. 1.
3 is a view showing in more detail a cross-section of a signal injection contact block (signal injection contact block) of the image sensor contrast ratio measuring device of FIG.
FIG. 4 is a diagram showing a digital current indicator, an analog current indicator, and a measured image display unit of the image sensor contrast ratio measuring apparatus of FIG. 1.
5A and 5B are diagrams illustrating an operation method of an image sensor contrast ratio measuring apparatus according to an embodiment.
6A shows a measurement image using an image sensor contrast ratio measuring apparatus using a conventional water droplet, and FIG. 6B shows a measurement image using an image sensor contrast ratio measuring apparatus according to an embodiment.

With reference to the accompanying drawings will be described in detail for the embodiment of the present invention to be easily carried out by those of ordinary skill in the art. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. In the drawings, parts not related to the description are omitted in order to clearly describe the present invention, and the same reference numerals are used for the same or similar elements throughout the specification. In the case of well-known technology, detailed description thereof will be omitted.

In the drawings, the thickness is enlarged to clearly express the various layers and regions. When a portion of a layer, film, region, plate, etc. is said to be “above” another portion, this includes not only the case “directly above” the other portion but also another portion in the middle. On the other hand, when one part is "just above" another part, it means that there is no other part in the middle. Conversely, when a portion of a layer, film, region, plate, or the like is said to be “under” another portion, this includes not only the case “underneath” another portion, but also another portion in the middle. On the other hand, when one part is "just below" another part, it means that there is no other part in the middle.

Throughout the specification, when a part “includes” a certain component, this means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

1 to 4, the image sensor contrast ratio measuring apparatus according to the embodiment is a compressed air injection bar (air compressor injection bar), signal injection contact block (signal injection contact block), front contact block guide (front contact block guide) , Square support, vertical support column, sensor support block, digital current indicator, analog current indicator, power switch , An up/down manipulation button, a signal injection wire, and a current measurement communication.

The air compressor injection bar can inject compressed air to control the operation of the front contact block guide in the vertical direction. The measuring device according to the embodiment does not use a separate motor, but uses compressed air.

For example, pressing the up and down operation button may move the front contact block guide downward, and pressing the up and down operation button once again may move the front contact block guide upward.

The sensor support block can support a capacitive sensor, for example, loading five or more sensors simultaneously.

The vertical support column supports the front contact block guide.

The signal injection contact block includes a damping cylinder, acryl support, and conductive carbon.

The image sensor contrast ratio measuring apparatus according to the embodiment measures the contrast ratio using conductive carbon instead of water droplets.

The conductive carbon may be fixed to the acrylic support by a fastening device such as a screw, may have a sheet shape, and may be disposed with a flat surface facing downward.

When the sensor to be measured is loaded on the sensor support block, and the front contact block guide moves downward, the conductive carbon comes into contact with the sensor surface, and the part where the conductive carbon comes into contact appears bright, and the part that does not contact the conductive member This dark image is generated and displayed on the measurement image display (see FIGS. 5A and 5B).

The conductive carbon may be black carbon, for example.

A damping rubber may be additionally disposed between the conductive carbon and the acrylic support to add elasticity.

The conductive carbon is connected to the signal injection wire. The signal injection wire may supply a pulse signal having a phase opposite to a coupling pulse generated inside the capacitive sensor to the conductive carbon. Contrast ratio measurement can be more accurately performed by the signal injection.

In the case of a conventional image sensor contrast ratio measuring apparatus using water droplets, signals are manually injected into the droplets using a very thin needle or a conductive metal plate having a smaller area than the droplets. However, in this case, since the signal is different depending on the inclination of the needle or the depth/area of contact, the measurement result may be uneven and inaccurate. In addition, since an electric signal is directly applied to the water droplets, there is a possibility that an electrical defect occurs in the sensor by the electrolysis reaction of the water droplets or the material on the sensor surface or the coating materials on the sensor surface by the water droplets reacting simultaneously. In the case of a conductive metal plate, there is a possibility of scratching or cracking on the surface of the sensor by foreign matters between the sensor and the metal plate before completely contacting the image sensor and the metal plate. In addition, when using a metal plate and water droplets at the same time, as in the case of a needle, the area of the water droplets between the image sensor and the metal plate is easy to be inaccurate, and the electrolysis of the water droplets causes the sensor surface itself (such as Cu) or the surface coating material of the sensor. It may have an effect.

On the other hand, in the image sensor contrast ratio measuring apparatus according to the embodiment, a uniform signal can be automatically supplied to the conductive carbon, so that the measurement result can be more uniform and accurate.

The results of evaluating the digital and analog current consumption consumed by the image sensor module (including image sensor, readout integrated circuits (ROIC) and flexible printed circuit board (FPCB)) are the digital current indicator and the analog current indicator ( analog current indicator), and the user can grasp the result therefrom. Meanwhile, the measured image is displayed on the measurement image display unit.

6A shows a measurement image using an image sensor contrast ratio measuring apparatus using a conventional water droplet, and FIG. 6B shows a measurement image using an image sensor contrast ratio measuring apparatus according to an embodiment. 6A and 6B are pictures generated using the same sensor, and the pulse signal injected into each has the same voltage condition.

6A and 6B, it can be seen that the contrast ratio of the picture generated by the image sensor contrast ratio measuring apparatus according to the embodiment is measured higher.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (1)

Compressed air injection bar, signal injection contact block, front contact block guide, square support, vertical support column, sensor Sensor support block, digital current indicator, analog current indicator, power switch, up/down manipulation button, signal injection wire wire), and an image sensor contrast ratio measuring apparatus including a measurement image display unit (current measurement communication).

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