JPH08304921A - Electronic developing type image pickup device - Google Patents

Abstract

PURPOSE: To obtain an electronic developing type image pickup device capable of performing photographing and readout operation with simple and compact constitution. CONSTITUTION: A movable reflector 50 holding a reflection mirror is turnably provided between an image pickup optical system 12 and an electronic developing type recording medium 30. A light source 42 is fixed below the reflector 50. When the reflector 50 is at a down-position, a subject image from the optical system 12 is reflected on the reflection surface of the reflection mirror opposed to the optical system 12 and guided to a finder 15. Parallel luminous fluxes emitted from the light source 42 are reflected on the reflection surface of the reflection mirror opposed to the recording medium 30 and guided to the recording medium 30. The light transmitted through the recording medium 30 forms an image by a scanner optical system 43 and the image is read out by a line sensor 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus using an electro-developing type recording medium for electronically developing an image obtained by photographing.

[0002]

2. Description of the Related Art Conventionally, a photographic material capable of electronically developing an optical image obtained by a taking lens has been known. For example, JP-A-5-2280 discloses an electrostatic information recording medium and a charge. A recording medium combined with a holding medium is disclosed. In this specification, such a recording medium is referred to as an electro-developing recording medium, and an imaging device using the electro-developing recording medium is referred to as an electro-developing imaging device.

In the electro-developing recording medium described in the above publication, the electrostatic information recording medium has a photoconductive layer and an inorganic oxide layer, and the charge holding medium has a liquid crystal display element. In this configuration, when the electrostatic information recording medium is exposed while voltage is applied to the electrostatic information recording medium and the charge holding medium, electric charges according to the amount of incident light are generated in the electrostatic information recording medium.
Since the strength of the electric field applied to the liquid crystal display element arranged facing the electrostatic information recording medium changes according to the generated charge, an image according to the light amount distribution is displayed or developed on the liquid crystal display element. .

[0004]

By the way, the transmitted light transmitted through the electro-developing recording medium is configured to be read by a line sensor or the like, and the optical image held on the electro-developing recording medium is immediately read out to the IC card. In the case of recording on a recording medium, the light from the light source needs to pass through the electro-developing recording medium during reading. On the other hand, at the time of photographing, the light source, the line sensor, etc. need to be retracted to a position off the optical axis. For example, a drive motor for driving the light source is provided, and the light source is arranged at a position facing the electro-developing recording medium only at the time of reading. However, in this case, because of the configuration for driving the light source,
The device itself becomes complicated and increases in size.

The present invention solves the above problems, and an object of the present invention is to obtain an electro-developing type image pickup device having a simple and compact structure and capable of photographing and reading operations.

[0006]

In order to solve the above-mentioned problems, an electro-developing type image pickup apparatus according to the present invention is arranged on an image forming plane of a subject image formed by an image pickup optical system, and the subject image is electronically formed. Provided between the image-capturing optical system and the electro-developing recording medium, which holds the optical information as optical information, and advances into the optical path of the image-capturing optical system at least when observing a subject and faces the image-capturing optical system. The reflection mirror that guides the light flux from the imaging optical system to the finder optical system for observing the subject by the first reflecting surface, the light source that illuminates the electro-developing recording medium, and the light that is emitted from this light source and passes through the electro-developing recording medium. Scanner optical system for forming an image of the emitted light beam, and a line sensor arranged at the image forming position by the scanner optical system to obtain electrical image information corresponding to the optical information recorded on the electro-developing recording medium. An electro-developing image pickup device comprising: a reflecting mirror, wherein a second reflecting surface for guiding the light flux from the light source to the electro-developing recording medium is formed on the surface of the reflecting mirror opposite to the first reflecting surface. It has a feature.

[0007]

The present invention will be described below with reference to illustrated embodiments. FIG. 1 is an external view of a still video camera to which an embodiment of the present invention is applied. This still video camera is an electro-developing image pickup device, and is configured to develop an image by an electro-developing recording medium.

When the camera body 11 is viewed from the front, a lens mounting opening 12c to which the image pickup optical system 12 (see FIG. 2) is mounted is formed in the substantially center of the front surface, and a finder 15 is provided above it. A release switch 14 is provided on the upper left side of the lens mounting opening 12c. When the release switch 14 is pressed halfway, the AF operation is performed, and when it is fully pressed, the shooting operation is performed. The strobe 13 is attached above the lens attachment opening 12c. The IC card C as a recording medium for recording the image signal obtained by the camera is attached and detached through a card insertion port (not shown) provided on the side surface of the camera body 11.

FIG. 2 is a sectional view of a still video camera, and FIG.
Is a block diagram. System control circuit 20
Is a microcomputer and controls the entire camera. The system control circuit 20 includes various switches such as the release switch 14, a display element 68 for displaying various setting states, a strobe drive circuit 23 for controlling light emission of the strobe 13, and various other components described later. Circuits and the like are connected to control various operations.

The image pickup optical system 12 is attached to the lens attachment opening 12c and has a plurality of lens groups 12b and a diaphragm 12a. Each lens group 12a moves to take a desired focus position during AF operation.

The electro-developing recording medium 30 is fitted into the opening 41a of the recording unit 41 and held by the recording unit 41. The recording unit 41 is meshed with one reduction gear connected to the drive motor 47. The drive motor 47 is driven by the control of the medium moving circuit 46, and the recording unit 41 moves in the vertical direction (sub-scanning direction) of FIG. Normally, the recording unit 41 is set at the initial position shown in FIG. 2, and at this time, the electro-developing recording medium 30 is
Image forming surface 12 of a subject image formed by the imaging optical system 12
placed on d. The electro-developing recording medium 30 is exposed while being applied with a voltage to develop a subject image formed by the imaging optical system 12 as a visible image as described later to electronically record optical information ( Optical image).

Imaging optical system 12 and electro-developing recording medium 30
A movable reflector 50 is provided between them so as to be rotatable around an axis perpendicular to the optical axis. The movable reflector 50 is provided with a reflection mirror 51 (see FIG. 6).
A finder optical system 15a for observing an object is disposed above the illuminator, and guides the light guided from the movable reflector 50 to the finder 15. The movable reflector 50 is normally (at least when observing an object) advanced into the optical path of the imaging optical system 12 and is set at a down position (inclined state shown by a solid line), and the light passing through the imaging optical system 12 is viewed by the finder optical system. Although guided to the system 15a, under the control of the exposure control circuit 27 during the image pickup operation, it is rotated upward by the mirror drive circuit 25 to the up position (horizontal state shown by the broken line), that is, from the image pickup optical system 12 to the electronic development. The subject image from the imaging optical system 12 is imaged on the electro-developing recording medium 30 by being set at a photographing position deviated from the path of light guided to the recording medium 30. After the exposure operation on the electro-developing recording medium 30 is completed, the movable reflector 50 is
Is returned to the original down position again.

A shutter 22 is provided between the movable reflector 50 and the electro-developing recording medium 30. Shutter 22
Is normally closed, but during imaging and reading operations, the shutter drive circuit 26 opens for a predetermined time under the control of the exposure control circuit 27, whereby the light guided from the imaging optical system 12 or the light source 42 is electrodeveloped recording. Medium 30
Be led to.

The diaphragm 12a, the movable reflector 50, and the shutter 22 are driven by an iris drive circuit 24, a mirror drive circuit 25, and a shutter drive circuit 26, respectively, and these circuits 24, 25, and 26 are exposed.
Controlled by 7. The exposure control circuit 27 operates according to a command signal output from the system control circuit 20. That is, during exposure control, the aperture of the diaphragm 12 a is adjusted by the iris drive circuit 24 according to the control of the exposure control circuit 27 based on the output signal from the photometric sensor 28.

Further, the scanner camera reads out an optical image held on the electro-developing recording medium 30 and, for example, I
It has a function of recording on a memory medium such as a C card C, and has a light source 42, a scanner optical system 43, and a line sensor 4.
4, the IC card holding unit 18 that holds the IC card C, the medium reading circuit 45, the medium moving circuit 46, and the amplifier 6
1, a circuit board 17 (see FIG. 2) provided with an A / D converter 62, an image processing circuit 63, an interface circuit 65 and the like.

A light source 4 for illuminating the electro-developing recording medium 30.
Reference numeral 2 is fixed below the movable reflector 50, which is out of the path of the light guided from the imaging optical system 12 to the electro-developing recording medium 30, and is attached to the fixed frame 48. Light source 4
As shown in FIG. 4, the reference numeral 2 indicates a support frame 42a and the support frame 4a.
A plurality of light emitting elements (LEDs, light emitters) supported by 2a
42b and a collimating lens array 42 of an optical system for emitting the light beam emitted from the light emitting element 42b as a parallel light beam.
c and. The light emitting element 42b and the collimator lens array 42c are arranged in the horizontal direction, and as shown in FIG. The reflection mirror 51 provided is irradiated. Note that a continuous linear light emitting element may be provided instead of the configuration in which the plurality of light emitting elements 42b are arranged in this way. Further, the light source is preferably one having a blue wavelength of about 450 n, which is excellent in the scattering property of the electro-developing recording medium 30.

The scanner optical system 43 comprises a total reflection mirror 43b, a scanner lens 43a and a total reflection mirror 43c which are vertically arranged behind the electro-developing recording medium 30 in FIG. The transmitted light that has passed is imaged on an image forming surface on which the light receiving surface of the line sensor 44 is arranged. The scanner lens 43a is a relay lens system whose constituent lenses are symmetrical. Therefore, the optical path length from the image forming surface 12d of the subject image on the electro-developing recording medium 30 to the incident surface of the scanner lens 43a, and the scanner lens 43a. The optical path lengths from the exit surface to the light receiving surface of the line sensor 44 are equal, and therefore the object imaging surface 12d and the light receiving surface of the line sensor 44 are optically symmetrical.
In other words, the image surface on the electro-developing recording medium 30 and the light receiving surface of the line sensor 44 are respectively the scanner optical system 43.
It is located at the focal position of.

The total reflection mirror 43b is arranged at a predetermined angle on the optical axis of the transmitted light transmitted through the electro-developing recording medium 30, and guides the transmitted light to the scanner lens 43a arranged below. The total reflection mirror 43c guides the transmitted light collected by the scanner lens 43a to the line sensor 44 arranged on the left side of the total reflection mirror 43c in FIG. Thus, total reflection mirrors 43b, 4
The transmitted light is refracted by 3c, and the transmitted light is recorded by the recording unit 4
Since it is configured to be guided along the outside of the required space by the movement of 1, the scanner optical system 43 and the line sensor 44 can be efficiently arranged, and the apparatus itself can be made compact.

The line sensor 44 is fixed such that its light receiving surface is arranged on the image forming surface of the scanner optical system 43, and obtains electrical image information corresponding to the optical image of the transmitted light. The line sensor 44 is, for example, a CC having 4096 pixels.
A D1 dimensional sensor is used.

The amplifier 61 amplifies the pixel signal output from the line sensor 44, and the A / D converter 62 converts the pixel signal into a digital signal. In the image processing circuit 63,
The digital signal is subjected to processes such as shading correction, dropout correction and gamma correction to be converted into predetermined image information, and then temporarily stored in a memory. In the interface circuit 65, the image information read from the memory is subjected to image compression, pixel data thinning, interpolation processing,
Processing such as image compression or format conversion is performed, and output to and recorded in the IC card C that is a memory medium.

During the read operation, the light source 42, the line sensor 44, and the medium moving circuit 46 are driven and controlled by the medium reading circuit 45, and the amplifier 61, the A / D converter 62, the image processing circuit 63, the interface circuit 65, etc. are in the system. It is controlled by the control circuit 20.

FIG. 6A is a sectional view of the movable reflector,
(B) is a front view. The movable reflector 50 includes a reflection mirror 51, a support member 52, and a rotation shaft 53. The reflection mirror 51 is a so-called quick return mirror, and is engaged with a support portion 52 a recessed in the support member 52 and fixed to the support member 52 in a mounted state. An opening 52b is formed near the center of the bottom surface of the support 52a, and the reflecting surface H of the reflecting mirror 51 is formed through the opening 52b.
2 is exposed to the outside. The rotation shaft 53 penetrates the shaft hole formed in the upper edge of the support member 52,
Can be rotated around the rotary shaft 53.

When the reflection mirror 51 is set to the down position shown in FIG. 2, the angle formed by the optical axis of the image pickup optical system 12 and the reflection surface H1 of the reflection mirror 51 and the parallel light flux emitted from the light source 42. The respective members such as the imaging optical system 12 and the light source 42 are arranged so that the angle formed by the optical axis and the reflection surface H2 of the reflection mirror 51 becomes equal. One reflection surface H1 of the reflection mirror 51 is at a position inclined by 45 degrees with respect to the optical axis of the imaging optical system 12, and reflects the light flux from the imaging optical system 12 on the reflection surface H1.
Is deflected by 90 degrees toward the finder optical system 15a. At the same time, the reflection surface H2 on the opposite side of the reflection mirror 51 is also at a position inclined by 45 degrees with respect to the parallel light flux from the light source 42, and the light flux from the light source 42 is deflected by 90 degrees, so that the electro-developing recording medium 30 is formed. Is reflected. The light flux emitted from the light source 42 and reflected by the reflecting surface H2 becomes a light flux parallel to the optical axis of the imaging optical system 12, and is incident perpendicularly to the recording surface of the electro-developing recording medium 30. .

On the reflecting surfaces H1 and H2, a reflecting film is formed by applying a coating process for laminating and forming a thin film of a metal such as aluminum or silver or a thin film of a dielectric. More specifically, a total reflection film is formed on the reflecting surface H1 by metal vapor deposition, and the reflecting surface H2 has the highest reflectance in the vicinity of the wavelength, which has excellent scattering characteristics of the electro-developing recording medium. A reflective film having a multilayer film structure in which a metal thin film and a dielectric thin film are combined is formed. The reflective surface H2
Does not require a multi-layer coating over the entire
In this embodiment, the reflective film is formed only around the portion exposed from the opening 52b.

FIG. 7 is a diagram showing the structure of the recording area of the electro-developing recording medium 30, which is the same as that disclosed in Japanese Patent Laid-Open No. 5-2280. That is, the electro-developing recording medium 30 is the electrostatic information recording medium 31 and the charge holding medium 3.
2 and a power source 33. Electrostatic information recording medium 31
Is formed by laminating a substrate 34, an electrode layer 35, an inorganic oxide layer 36, and a photoconductive layer 37, and the photoconductive layer 37 is formed by polymerizing a charge generation layer 37a and a charge transport layer 37b. The charge holding medium 32 is configured by enclosing the liquid crystal 40 between the liquid crystal support 38 and the liquid crystal electrode layer 39. The charge transport layer 37b of the electrostatic information recording medium 31 and the liquid crystal support 38 of the charge holding medium 32 face each other with a minute gap.

The power supply 33 is on / off controlled by the recording medium recording circuit 29, and when the power supply 33 is in the on state, the electrode layer 3
5 and the liquid crystal electrode layer 39, that is, the electrostatic information recording medium 3
A voltage is applied to 1 and the charge holding medium 32. When the electrostatic information recording medium 31 is exposed in this voltage applied state, charges are generated on the electrostatic information recording medium 31 according to the image. Since the strength of the electric field acting on the liquid crystal 40 changes according to this charge, the image is displayed on the liquid crystal 40 as a visible image, and the subject image is developed. The charge holding medium 32 is a dispersion type liquid crystal display element, and the developed visible image is held even if the electric field is removed. The dispersed liquid crystal display element can erase the developed visible image by heating it to a predetermined temperature using a heating device (not shown). In that case, the same recording medium can be repeatedly used. it can.

FIGS. 8A and 8B are views showing the vicinity of the recording unit. FIG. 8A shows the state at the start of reading, FIG. 8B shows the state at the end of the reading operation, and FIG. 8C shows the state of the initial position.

Normally, the recording unit 41 is set at the initial position shown in FIG. 8C, and the movable reflector 50 is set at the down position (see FIG. 2). At the time of shooting, the subject image guided from the imaging optical system 12 is reflected by the reflecting surface H1 of the reflecting mirror 51 and is guided to the finder 15 via the finder optical system 15a.

When the release switch 14 is half-pressed in this state, the AF operation is performed based on the photometric result of the photometric sensor 28, and the taking lens group 12b moves to the focus position. Then, when the release switch 14 is fully pressed, the aperture of the diaphragm 12a is changed from the fully opened state to a predetermined aperture, and the movable reflector 50 is moved from the down position to the up position (see FIG. 2) so that the subject image It is set to a state in which the photographing operation can be performed by retracting from the optical axis. In this state, the shutter 22 is opened for a predetermined time, and the subject image guided from the imaging optical system 12 is formed on the electro-developing recording medium 30.
A voltage is applied to the electro-developing recording medium 30 to develop the subject image as an optical image. This optical image is retained even when the output of the recording medium activation signal (application of voltage to the electro-developing recording medium) is stopped.

After that, when it is confirmed that the movable reflector 50 has returned to the down position and the diaphragm 12a has returned to the initial state, the driving of the movable reflector 50 and the diaphragm 12a is stopped, and the image pickup operation ends.

Next, the read operation will be described. When the signal indicating the end of the imaging operation is received, the shutter 22 is opened and the drive motor 47 is rotated in the normal direction to cause the recording unit 41 to rotate.
Is lowered to the reading start position shown in FIG. The drive amount and the total drive amount of the drive motor (pulse motor) 47 are grasped and controlled by the system control circuit 20 via the medium moving circuit 46.

Then, the light source 42 is turned on, and the light from the light source 42 is reflected on the reflection surface H2 of the reflection mirror 51 and guided to the electro-developing recording medium 30. The reflection mirror 51 is the light source 4
The light, which is sufficiently larger than the illumination area by the parallel light flux of 2, enters the illumination area of the light source 42, that is, the reading area of the line sensor 44. The transmitted light transmitted through the electro-developing recording medium 30 is imaged on the light receiving surface of the line sensor 44 via the scanner optical system 43, and the line sensor 44 outputs the image information corresponding to this optical image to the amplifier 61.
The image information is recorded in the IC card C after being subjected to predetermined processing by the amplifier 61, the A / D converter 62, the image processing circuit 63, and the interface circuit 65.

When the reading operation for one horizontal scanning line is completed, the drive motor 47 is rotated in the reverse direction, and the recording unit 41 is raised by the next one horizontal scanning line and stopped, and similarly, it corresponds to the next scanning line. The optical image is read out. In this way, the recording unit 41 repeatedly scans for a predetermined time and moves for a predetermined amount, whereby the optical images recorded and formed on the electro-developing recording medium 30 are sequentially read and recorded on the IC card C. .

When the total driving amount of the reverse rotation drive reaches a predetermined value and reading of all horizontal scanning lines is completed, the recording unit 4
1 is located at the reading end position shown in FIG. 8B, the drive power of the line sensor 44 is switched to the OFF state, the light source 42 is turned off, and the shutter 22 is closed. Next, the drive motor 47 is driven to rotate normally, and after the recording unit 41 is set to the initial position (the position shown in FIG. 8C), the drive motor 47 stops. The operation of detecting the initial position of the electro-developing recording medium 30 is performed based on a signal output when a part of the electro-developing recording medium 30 crosses a photo interrupter (not shown).

After that, when all the images of the read image signal are recorded in the IC card C, the amplifier 61, the A / D converter 62, etc. are stopped, and the reading operation is completed.

As described above, in this embodiment, at the time of photographing, the subject image from the image pickup optical system 12 is reflected by the reflecting surface H1 of the reflecting mirror 51 and guided to the finder 15, and
At the time of reading, the electro-developing recording medium 30 is irradiated with the light from the light source 42 via the reflecting surface H2 of the reflecting mirror 51, and the transmitted light is read by the line sensor 44, which complicates the apparatus. Without the light source 42
Can be fixedly provided at a position off the optical axis of the subject image, and the device itself can be made simple and compact.

In the present embodiment, the reading operation is started immediately after the photographing operation is finished. However, for example, a reading start switch is provided, and the reading operation is started by operating this start switch. You may comprise.

[0038]

As described above, according to the present invention, it is possible to obtain an electro-developing type image pickup device having a simple and compact structure and capable of performing photographing and reading operations.

[Brief description of drawings]

FIG. 1 is an external view of a still video camera to which an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view of the still video camera of FIG.

3 is a block diagram showing a circuit configuration of the still video camera of FIG. 1. FIG.

FIG. 4 is a diagram showing an arrangement of light emitting elements and collimator lenses in a light source.

FIG. 5 is a diagram showing an operation of a collimating lens.

6A and 6B are views showing a movable reflector, in which FIG. 6A is a sectional view and FIG. 6B is a front view.

FIG. 7 is a diagram showing a configuration of an electro-developing recording medium.

8A and 8B are diagrams of the vicinity of a recording unit, where FIG. 8A shows the state at the start of reading, FIG. 8B shows the state at the end of the reading operation, and FIG.

[Explanation of symbols]

 11 camera body 12 imaging optical system 15 viewfinder 20 system control circuit 30 electro-developing recording medium 41 recording unit 42 light source 43 scanner optical system 44 line sensor 50 movable reflector 51 reflection mirrors H1, H2 reflection surface

[Procedure amendment]

[Submission date] May 13, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

Next, the read operation will be described. When the signal indicating the end of the imaging operation is received, the shutter 22 is opened and the drive motor 47 is rotated in the normal direction to cause the recording unit 41 to rotate.
Rises and is set at the reading start position shown in FIG. The drive amount and total drive amount of the drive motor (pulse motor) 47 are grasped and controlled by the system control circuit 20 via the medium moving circuit 46.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

[0033] 1 when the reading operation of the horizontal scanning line is completed, the drive motor 47 is reversed, the recording unit 41 is stopped by lowering only the following one horizontal scanning line, Part 1 in the same manner
An optical image corresponding to the horizontal scanning line segment is read out. By thus recording unit 41 repeatedly scans the movement of the stop and an amount predetermined time, the optical image recorded formed on the electro-developing recording medium 30 is recorded is read out sequentially in the IC card C .

Claims (8)

[Claims] 1. An electro-developing recording medium, which is arranged on an image forming surface of a subject image formed by an imaging optical system and electronically holds the subject image as optical information, the imaging optical system and electronic development. Provided between the mold recording medium and at least when observing an object, the light beam from the imaging optical system for observing the object is advanced by the first reflecting surface that is in the optical path of the imaging optical system and faces the imaging optical system. A reflection mirror that guides to the finder optical system, a light source that illuminates the electro-developing recording medium, a scanner optical system that forms an image of a light beam emitted from the light source and transmitted through the electro-developing recording medium, and the scanner optical system. An electro-developing image pickup device, comprising: a line sensor, which is arranged at an image-forming position of a system and which obtains electrical image information corresponding to optical information recorded on the electro-developing recording medium, The surface opposite to the first reflecting surface of the reflecting mirror, the guiding light beam from said light source to said electro-developing recording medium 2
An electro-developing image pickup device having a reflecting surface. 2. The electro-developing image pickup device according to claim 1, wherein the light source includes a light emitting body and an optical system for emitting a light beam emitted from the light emitting body as a parallel light beam. 3. In the light source, a light flux reflected by a second reflection surface of the reflection mirror is recorded on a recording surface of the electro-developing recording medium in a state where the reflection mirror advances into an optical path of an image pickup optical system. The electro-developing image pickup device according to claim 2, wherein the electro-developing image pickup device is arranged at a position such that it is vertically incident. 4. The light source, when the reflection mirror is in the optical path of the image pickup optical system, the angle between the optical axis of the image pickup optical system and the first reflection surface of the reflection mirror, and the light source from the light source. 3. The electro-developing image pickup device according to claim 2, wherein the electro-developing image pickup device is arranged at a position where an optical axis of a principal ray emitted and an angle formed by the second reflecting surface of the reflecting mirror are equal to each other. 5. The reflection mirror is mounted on a support member having an opening for exposing the second reflection surface, and the support member is placed outside the subject observation position and the optical path of the imaging optical system. The electro-developing image pickup device according to claim 1, wherein the electro-developing image pickup device is supported so as to be movable to a retracted photographing position. 6. The electro-developing image pickup device according to claim 1, further comprising a recording unit that performs a predetermined process on the image information and records the image information on a recording medium. 7. The electro-developing image pickup apparatus according to claim 1, further comprising: a recording unit that holds the electro-developing recording medium; and a moving unit that moves the recording unit in a predetermined direction. 8. The electro-developing image pickup device according to claim 1, wherein the first reflecting surface and the second reflecting surface are each subjected to a predetermined coating treatment.