Optical sensor device

An optical sensor device comprising:

• a light-projecting optical system for projecting light toward an object to be sensed, said projected light having the characteristic that it is not separated into a plurality of polarized light beams by said light-projecting optical system;
• and
• a light-receiving optical system upon which reflected light, transmitted light or scattered light from the object to be sensed impinges;
• said light-projecting optical system including at least a light-emitting element for outputting projected light;
• and
• said light-receiving optical system including:
• a polarization beam splitter for separating the reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence, said polarization beam splitter having a light separating characteristic that is substantially constant within a range of wavelength spread exhibited by the projected light from said light-emitting element;
• a first light-receiving element for receiving the first luminous flux;
• and
• a second light-receiving element for receiving the second luminous flux.

An optical sensor device comprising:

• a light-projecting optical system for projecting light toward an object to be sensed, said projected light having the characteristic that it is not separated into a plurality of polarized light beams by said light-projecting optical system;
• and
• a light-receiving optical system upon which reflected light, transmitted light or scattered light from the object to be sensed impinges;
• said light-projecting optical system including at least a light-emitting element for outputting projected light;
• and
• said light-receiving optical system including:
• a polarization beam splitter for separating the reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence;
• a first light-receiving element for receiving the first luminous flux;
• and
• a second light-receiving element for receiving the second luminous flux.

A sensing method comprising the steps of:

• projecting projected light toward an object to be sensed, said projected light having the characteristic that it is not separated into a plurality of polarized light beams by said light-projecting optical system;
• using a polarization beam splitter having a light separating characteristic that is substantially constant within a range of angles of incidence used;
• separating reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence of said polarization beam splitter and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence of said polarization beam splitter;
• and
• outputting a signal relating to absence/presence of the object, surface property of the object or material constituting the object on the basis of quantity of light of the first luminous flux and quantity of light of the second luminous flux.

A sensing method comprising the steps of:

• projecting projected light toward an object to be sensed, said projected light having the characteristic that it is not separated into a plurality of polarized light beams by said light-projecting optical system;
• using a polarization beam splitter having a light separating characteristic that is substantially constant within a range of wavelength spread exhibited by the projected light;
• separating reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence of said polarization beam splitter and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence of said polarization beam splitter;
• and
• outputting a signal relating to absence/presence of the object, surface property of the object or material constituting the object on the basis of quantity of light of the first luminous flux and quantity of light of the second luminous flux.

A sensing method comprising the steps of:

• projecting projected light toward an object to be sensed, said projected light having the characteristic that it is not separated into a plurality of polarized light beams by said light-projecting optical system;
• separating, by using a polarization beam splitter, reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence of said polarization beam splitter and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence of said polarization beam splitter;
• and
• outputting a signal relating to absence/presence of the object, surface property of the object or material constituting the object on the basis of quantity of light of the first luminous flux and quantity of light of the second luminous flux.

An optical sensor device comprising:

• a light-projecting optical system for projecting light toward an object to be sensed;
• and
• a light-receiving optical system upon which reflected light, transmitted light or scattered light from the object to be sensed impinges;
• said light-projecting optical system including at least a light-emitting element for outputting projected light;
• and
• said light-receiving optical system including:
• a polarization beam splitter for separating the reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence, said polarization beam splitter having a light separating characteristic that is substantially constant within a range of angles of incidence used, and wherein said light separating characteristic is represented by:
• a first proportion expressed by a ratio of the quantity of light of the s-polarized component contained in the first luminous flux to the quantity of light of the s-polarized component incident upon said polarization beam splitter,
• a second proportion expressed by a ratio of the quantity of light of the p-polarized component contained in the second luminous flux to the quantity of light of the p-polarized component incident upon said polarization beam splitter, or
• the ratio of said first proportion to said second proportion;
• at least one of said first proportion and said second proportion or said ratio between them being held substantially constant;
• a first light-receiving element for receiving the first luminous flux;
• and
• a second light-receiving element for receiving the second luminous flux.

An optical sensor device comprising:

• a light-projecting optical system for projecting light toward an object to be sensed;
• and
• a light-receiving optical system upon which reflected light, transmitted light or scattered light from the object to be sensed impinges:
• a light-receiving lens for converging light incident upon said light-receiving optical system;
• said light-projecting optical system including at least a light-emitting element for outputting projected light;
• and
• said light-receiving optical system including:
• a polarization beam splitter for separating the reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly an s-polarized component with regard to the plane of incidence and a second luminous flux which is mainly a p-polarized component with regard to the plane of incidence, said polarization beam splitter having a light separating characteristic that is substantially constant within a range of angles of incidence used;
• a first light-receiving element for receiving the first luminous flux;
• and
• a second light-receiving element for receiving the second luminous flux.

An optical sensor device comprising:

• a light-projecting optical system for projecting light toward an object to be sensed;
• and
• a light-receiving optical system upon which reflected light, transmitted light or scattered light from the object to be sensed impinges;
• said light-projecting optical system including at least a light-emitting element for outputting projected light;
• and
• said light-receiving optical system including:
• a polarization beam splitter for separating the reflected light, transmitted light or scattered light from the object into a first luminous flux which is mainly a p-polarized component with regard to the plane of incidence, said polarization beam splitter having a light separating characteristic that is substantially constant within a range of angles of incidence used;
• a first light-receiving element for receiving the first luminous flux;
• a second light-receiving element for receiving the second luminous flux;
• and,
• a reflector provided to face said polarization beam splitter on a side from which the first or second luminous flux emerges, wherein the first or second luminous flux is reflected from said reflector.