Reflection characteristic measuring apparatus

Abstract

A reflection characteristic measuring apparatus includes: a light irradiating member for irradiating light toward a sample surface to be measured; a light detector, having a two-dimensional light receiving surface, for receiving reflection light from the sample surface illuminated with the light irradiated by the light irradiating member to output two-dimensional light receiving data concerning a first area corresponding to an area of the light receiving surface; an area setter for setting a second area at an appropriate position within the first area, the second area being smaller than the first area, to restrict light receiving data to be used in obtaining a reflection characteristic of the sample surface; and a calculator for obtaining a characteristic of the sample surface, based on two-dimensional light receiving data concerning the second area. The area setter detects whether the two-dimensional light receiving data concerning the first area includes a peak value concerning light receiving; sets the second area, with a position of the peak value being defined as a reference position, if the peak value is detected; and sets the second area, with a central position on the first area being defined as the reference position, if the peak value is not detected.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a reflection characteristic measuring apparatus according to an embodiment of the invention.

FIG. 2 is a diagram showing behaviors of light directed from a second lens element toward a sample surface to be measured, and of light directed from a third lens element toward an image sensor.

FIG. 3 is a diagram showing a relationship between an area W1 within which the light from the third lens element is irradiated onto a light receiving surface of the image sensor, and a light receiving area W2 of the image sensor.

FIG. 4 is a block diagram showing an electrical configuration of the reflection characteristic measuring apparatus.

FIG. 5 is an explanatory diagram showing an intensity distribution on reflection light with a peak value, in the case where the setting position of a sample surface is not changed.

FIG. 6 is an explanatory diagram showing an intensity distribution on reflection light with a peak value, in the case where the setting position of the sample surface is changed.

FIG. 7 is a flowchart showing a gloss measurement operation to be executed by the reflection characteristic measuring apparatus.

FIG. 8 is a diagram for describing an approach for detecting a peak position.

FIG. 9 is a diagram showing a second modified embodiment.

FIG. 10 is a diagram showing a reflection characteristic measuring apparatus according to a conventional art.

FIGS. 11, 12, 13A, and 13B are diagrams for describing drawbacks involved in the conventional art.

Claims

1. A reflection characteristic measuring apparatus, comprising: a light irradiating member for irradiating light toward a sample surface to be measured;a light detector, having a two-dimensional light receiving surface, for receiving reflection light from the sample surface illuminated with the light irradiated by the light irradiating member to output two-dimensional light receiving data concerning a first area corresponding to an area of the light receiving surface;an area setter for setting a second area at an appropriate position within the first area, the second area being smaller than the first area, to restrict light receiving data to be used in obtaining a reflection characteristic of the sample surface; anda calculator for obtaining a characteristic of the sample surface, based on two-dimensional light receiving data concerning the second area, whereinthe area setter detects whether the two-dimensional light receiving data concerning the first area includes a peak value concerning light receiving,the area setter sets the second area, with a position of the peak value being defined as a reference position, if the peak value is detected, andthe area setter sets the second area, with a central position on the first area being defined as the reference position, if the peak value is not detected.

2. The reflection characteristic measuring apparatus according to claim 1, further comprising: an optical system for directing the reflection light from the sample surface toward the light receiving surface of the light detector, whereinthe optical system is operable to allow specular reflection light from the sample surface set within a predetermined angular range to be incident onto the area of the light receiving surface of the light detector.

3. The reflection characteristic measuring apparatus according to claim 1, wherein the light irradiating member includes a light source for emitting light, and a first optical system for directing the light emitted by the light source toward the sample surface,the apparatus further comprises a second optical system for directing the reflection light from the sample surface toward the light receiving surface of the light detector,the first optical system is an optical system having a first lens element and a diaphragm,the second optical system is an optical system having a second lens element, the second optical system substantially excluding a diaphragm,the diaphragm and the light receiving surface of the light detector are positioned in optically conjugated relations with each other, andthe second lens element has such a focal length that specular reflection light from the sample surface set within a predetermined angular range is allowed to be incident onto the area of the light receiving surface of the light detector.

4. The reflection characteristic measuring apparatus according to claim 1, wherein the light detector includes an area sensor having pixels arrayed in a matrix.

5. The reflection characteristic measuring apparatus according to claim 4, wherein the calculator executes the following first to third processes:the first process of calculating the sum of light receiving data concerning each of horizontal pixel arrays in a horizontal direction of the area sensor to determine a horizontal pixel array having a maximal sum among the sums concerning the horizontal pixel arrays;the second process of calculating the sum of light receiving data concerning each of vertical pixel arrays in a vertical direction of the area sensor to determine a vertical pixel array having a maximal sum among the sums concerning the vertical pixel arrays; andthe third process of setting the position of a pixel that belongs both to the horizontal pixel array having the maximal sum obtained in the first process, and to the vertical pixel array having the maximal sum obtained in the second process, as a position of the peak value.

6. The reflection characteristic measuring apparatus according to claim 1, wherein the characteristic of the sample surface is a characteristic concerning gloss of the sample surface.

7. A reflection characteristic measuring apparatus, comprising: a light irradiating member for irradiating light toward a sample surface to be measured;a light detector, having a two-dimensional light receiving surface, for receiving reflection light from the sample surface illuminated with the light irradiated by the light irradiating member to output two-dimensional light receiving data concerning a first area corresponding to an area of the light receiving surface;an optical system for directing the reflection light from the sample surface toward the light receiving surface of the light detector;an area setter for setting a second area at an appropriate position within the first area, the second area being smaller than the first area, to restrict light receiving data to be used in obtaining a reflection characteristic of the sample surface; anda calculator for obtaining a characteristic of the sample surface, based on two-dimensional light receiving data concerning the second area, whereinthe optical system is operable to allow specular reflection light from the sample surface set within a predetermined angular range to be incident onto the area of the light receiving surface of the light detector, andthe area setter sets the second area based on an incident position of the specular reflection light onto the light receiving surface of the light detector.

8. A reflection characteristic measuring apparatus, comprising: a light source for emitting light;a first optical system for directing the light emitted by the light source toward a sample surface to be measured;a light detector, having a two-dimensional light receiving surface, for receiving reflection light from the sample surface illuminated with the light emitted by the light source to output two-dimensional light receiving data concerning a first area corresponding to an area of the light receiving surface;a second optical system for directing the reflection light from the sample surface toward the light receiving surface of the light detector;an area setter for setting a second area at an appropriate position within the first area, the second area being smaller than the first area, to restrict light receiving data to be used in obtaining a reflection characteristic of the sample surface; anda calculator for obtaining a characteristic of the sample surface, based on two-dimensional light receiving data concerning the second area, whereinthe first optical system is an optical system having a first lens element and a diaphragm,the second optical system is an optical system having a second lens element, the second optical system substantially excluding a diaphragm,the diaphragm and the light receiving surface of the light detector are positioned in optically conjugated relations with each other,the second lens element has such a focal length that specular reflection light from the sample surface set within a predetermined angular range is allowed to be incident onto the area of the light receiving surface, andthe area setter sets the second area based on an incident position of the specular reflection light onto the light receiving surface.

9. A reflection characteristic measuring apparatus, comprising: a light irradiating member for irradiating light toward a sample surface;a light detector, having a plurality of light receiving units arrayed in a line, for receiving reflection light from the sample surface illuminated with the light to output data relating to the plurality of light receiving units;an area setter for setting a specific area being smaller than an area of the plurality of light receiving units to restrict light receiving data to be used in obtaining a reflection characteristic of the sample surface; anda calculator for obtaining a characteristic of the sample surface, based on the data relating to the plurality of light receiving units concerning the specific area, whereinthe area setter detects whether the data relating to the plurality of light receiving units includes a peak value concerning light receiving,the area setter sets the specific area, with a position of the peak value being defined as a reference position if the peak value is detected, andthe area setter sets the specific area, with a central position on the area of the plurality of light receiving units being defined as a reference position, if the peak value is not detected.