KR0179620B1 - Light intensity control device - Google Patents

Abstract

The present invention relates to a light intensity adjusting apparatus applicable to a laser projector, and more particularly to a light intensity adjusting apparatus applicable to a laser projector, which comprises a polarizing plate or a polarizing prism 22 for polarizing light emitted from a light source 20 in a predetermined direction, A polarization direction rotating member 24 for rotating the polarization direction of the light with respect to the light in a variable thickness direction, and a photomultiplier plate 26 or a photomasking prism 26 for detecting light whose polarization direction is varied by the polarization direction rotating member 24, The polarization direction rotating member 24 is constituted by first and second deforming portions 40 and 50 formed on the single base plate 30 so as to be compressed / expanded in mutually opposing directions in accordance with an electric field or a magnetic field, The first and second deformed portions 50 are formed on a single base plate 30 and each have a first electrode 42 and a second electrode 44 to which an electric field or a magnetic field is applied, 1 and the second electrode 42, 44 (52, 54) (46, 56) whose expansion ratio is varied by an electric or magnetic field applied to the first and second electrodes (42, 44; 52, 54) And a variable member layer (48; 58) whose one side surface is tapered to have a constant inclination angle, and the polarization direction rotating member (24) has a variable thickness The sub-panel 90 having a polarization direction different from that of the variable member layers 48 and 58 is provided for the purpose of compensating the transmittance for the sufficient light modulation effect even in the case of approximating to? / 2.

Description

Light intensity control device

FIG. 1 is a schematic view for explaining a configuration of a light intensity adjusting apparatus according to a conventional example; FIG.

FIG. 2 is a view for explaining a configuration of a light intensity adjusting apparatus according to an embodiment of the present invention; FIG.

Fig. 3 is a schematic view for explaining the structure of the polarization direction rotating member shown in Fig. 2; Fig.

Fig. 4 is a view for explaining the action of the polarization direction rotating member shown in Fig. 3;

FIG. 5 is a view showing a polarization direction rotating member of the light intensity adjusting apparatus according to another embodiment of the present invention. FIG.

FIG. 6 is a view for explaining a projection degree relationship with respect to a polarization angle by the light intensity adjusting apparatus according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10,20: light source 12,22: polarizer (polarizing prism)

14: light control device 16, 26:

24, 24 ': polarization direction rotating member 30, 60: base plate

40, 50: first and second deformations 42, 44: first and second electrodes

46: Piezoelectric material layer 48: Variable member layer (photoactive medium)

52, 54: first and second electrodes 56: piezoelectric material layer

58: variable member layer (photoactive medium) 70,80: first and second deformable parts

72, 74: first and second electrodes 76, 86: piezoelectric material layer

78,88: Variable member layer (photoactive medium)

The present invention relates to a light intensity control device applicable to a laser projector, and more particularly, to a light intensity control device applicable to a laser projector, and more particularly to a light intensity control device capable of controlling the light intensity by adjusting the rotation rate of the polarization direction of the light transmitted through the piezoelectric material and the piezoelectric material, To a light intensity control device for controlling the light intensity.

2. Description of the Related Art In general, a light intensity adjusting device for obtaining a constant amount of light by modulating a laser beam emitted from a light source employs a light modulating member that variably changes the transmittance based on an electric field applied to incident light.

FIG. 1 is a schematic view for explaining a configuration of a light intensity adjusting apparatus according to a related art example. In FIG. 1, reference numeral 10 denotes a light source for emitting laser light, 12 denotes a light source, A polarizing plate or a polarizing prism. Reference numeral 14 denotes a polarizing plate or a light modulating member which modulates the light polarized by the polarizing prism 12 by an applied electric field to change the polarizing direction and 16 denotes a polarizing direction And a photomultiplier or a prism that scatters the changed light and scans the final light amount.

As the light modulating member 14, an LCD device to which a method of adjusting an amount of light to be emitted by scattering an arrangement state by a voltage signal applied from a uniform arrangement state of liquid crystal is applied, or an LCD device in which a polarizing plane of crystal is applied with an electric field or a magnetic field The Kerr cell using the Kerr effect of rotating phenomenon or the Pockels effect by which the birefringence is generated when an electric field is applied to the medium is used.

1, the laser beam emitted from the light source 10 is polarized so as to have a certain direction by the polarizing plate or the polarizing prism 12, and the polarized light is transmitted through the light modulating member 14, When the light modulating member 14 is an LCD device, a liquid crystal array of the LCD device is scattered by a polarizing plate responsive to a voltage level applied to the LCD device, and the light modulating member 14 In the case of a Kerr cell or a Poelz cell, the amount of polarization of the incident light is adjusted according to an applied electric field or a magnetic field, whereby the light modulated by the light modulating member 14 is modulated to an appropriate degree. The light transmitted through the light modulating member 14 is polarized at a constant angle relative to a point of time when the light is emitted from the light source 10 and a polarizing direction different from that of the polarizing plate or the polarizing prism 12 The light modulating member 14 can detect the light with the adjusted amount of polarization.

Here, when the light intensity adjusting apparatus shown in Fig. 1 is applied to a projection type image display system such as a laser projector, the light modulating member 14 is applied with an electric field or a magnetic field derived from a voltage corresponding to an image signal The intensity-adjusted light corresponding to the image signal can be obtained.

However, according to the conventional apparatus for adjusting the light intensity, the laser light emitted from the light source 10 is modulated by adjusting the polarization direction of the light polarized in a predetermined direction in the polarizing plate or the polarizing prism 12 In the case where the light modulation member 14 is constituted by, for example, an LCD device, the scattering action of the liquid crystal array by the polarizing plate is accompanied by a delay time, so that it is difficult to secure high speed optical modulation response characteristics, Or a PoC cell, the cost is increased.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an optical intensity adjusting device capable of varying the thickness of a piezoelectric material with respect to an applied signal, .

Another object of the present invention is to provide a light intensity adjusting device capable of obtaining a reliable light modulation effect even when the change in the transmittance of light is small while securing a high optical modulation response time by varying the thickness of the piezoelectric material with respect to an applied signal .

According to a preferred embodiment of the present invention, there is provided a polarizing device comprising: polarizing means for polarizing light emitted from a light source in a predetermined direction; polarizing means for polarizing light polarized in a direction There is provided a light intensity adjusting apparatus comprising a rotating means and a light-analyzing means for measuring light whose polarization direction is varied by the direction of polarization rotating means.

Preferably, the polarization direction rotating means is constituted by first and second deforming portions formed on a single base plate so as to be compressed / expanded in mutually opposing directions in accordance with an electric field or a magnetic field, A first electrode which is fixed on a single base plate and is movable with respect to a first electrode to which an electric field or a magnetic field is applied and a second electrode which is movable between an electric field or a magnetic field applied between the first and second electrodes, And a variable member layer formed by a photoactive medium formed to have a predetermined inclination angle by tapering at one side of the piezoelectric material layer.

According to the present invention, the mutually facing side surfaces of the variable member layers of the first and second deformed portions are tapered, and the tapered surfaces of the respective deformable member layers are mirror-polished, and the variable member layers Is formed of any one material selected from an anisotropic material, preferably quartz, MgF ₂ , or CdS.

According to another embodiment of the present invention, there is provided a polarizing device comprising: a polarizing means for polarizing light emitted from a light source in a predetermined direction; and a polarizing means for adjusting the polarization direction of the polarized light with varying thickness, A polarization direction rotating means equipped with an auxiliary panel means for compensating a rotation angle of the polarization direction in a small case, and a light-analyzing means for measuring light whose polarization amount is varied by the polarization direction rotating means.

Preferably, the polarization direction rotating means is constituted by first and second deforming portions formed on a single base plate so as to be compressed / expanded in mutually opposing directions in accordance with an electric field or a magnetic field, A first electrode and a second electrode which are fixed on a single base plate and are applied with an electric field or a magnetic field, an expansion ratio of the first electrode and the second electrode interposed between the first and second electrodes, And a flexible member layer which is formed to be in contact with the second electrode and tapered at one side thereof to have a predetermined inclination angle.

According to the present invention, the mutually facing side surfaces of the variable member layers of the first and second deformed portions are tapered, and the tapered surfaces of the respective deformable member layers are mirror-polished, and the variable member layers Is formed of any one material selected from an anisotropic material, preferably quartz, MgF ₂ , or CdS.

In addition, the sub-panel means is formed of a member whose polarization rotation direction is different from that of the variable member layer of the first and second deforming portions.

Therefore, when the light emitted from the light source is applied to the polarization direction rotating means in a state where the light emitted from the light source is polarized in a predetermined direction by the polarizing plate or the polarization prism, The piezoelectric material layer is inflated in accordance with the level of the electric field or magnetic field applied to the first and second electrodes of the first and second deforming parts constituting the piezoelectric material layer, The polarization direction is rotated in such a manner that the thickness of the variable member layer is varied and the light modulated by the light transmitted through the polarization direction rotating means is photographed by the light analyzing means. Further, when the transmittance of the light transmitted through the polarization direction rotating means and scatted by the light measuring means is small, a sufficient light modulation effect can be obtained by the application of the sub panel means.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic view showing a light intensity adjusting apparatus according to an embodiment of the present invention. In FIG. 2, reference numeral 20 denotes a light source for emitting laser light, and 22 denotes a light source 20 for polarizing light emitted from the light source 20 in a predetermined pattern Polarizer or polarizing prism. Reference numeral 24 denotes a polarizing plate or polarization direction rotating member for modulating the light polarized by the polarizing prism 22 by an applied electric field to rotate the polarization direction. Reference numeral 26 denotes a polarization direction rotating member And a photometric plate or a prism that scans the light with the angle compensated to measure the final amount of light.

Here, according to an embodiment of the present invention, the polarization direction rotating member 24 is arranged on the single base plate 30 as shown in FIG. 3 so as to compress / expand in a direction opposite to the electric field or the magnetic field, The first and second deforming portions 40 and 50 are formed.

The first deformed portion 40 is formed on the single base plate 30 and includes a first electrode 42 and a second electrode 44 to which an electric field or a magnetic field is applied, (44), and the piezoelectric material layer (46) interposed between the first and second electrodes (44, 44) and whose expansion ratio is varied by an electric field or a magnetic field applied to the first and second electrodes And a variable member layer 48 made of a photoactive medium formed to be tapered at one side surface 48a and having a predetermined inclination angle. Preferably, the first electrode 42 is fixed on the base plate 30 and applied as a common electrode, while the second electrode 44 is electrically insulated from the base plate 30, And is displaced in accordance with the expansion / contraction state of the valve 46. The tapered surface 48a of the deformable member layer 48 of the first deformable portion 40 is mirror finished and preferably the deformable member layer 48 of the first deformable portion 40 is made of an anisotropic material, And is preferably formed of any one material selected from quartz, MgF ₂ , or CdS.

The second deforming part 50 is formed on the single base plate 30 similar to the structure of the first deforming part 40 and is formed with a first electrode 52 to which an electric field or a magnetic field is applied, A variable second electrode 54 and a piezoelectric element 52 interposed between the first and second electrodes 52 and 54 and having an expansion ratio varied by an electric field or a magnetic field applied to the first and second electrodes 52 and 54, The material layer 56 is in contact with the second electrode 54 while being kept in contact with the tapered surface 48a of the deformable member layer 48 of the first deforming portion 40, The side surface 58a is tapered to have a variable member layer 58 made of a photoactive medium formed to have a predetermined inclination angle.

The first electrode 52 is fixed on the base plate 30 and applied as a common electrode while the second electrode 54 is electrically insulated from the base plate 30 to form the piezoelectric material layer 56 in the direction of expansion / contraction. The tapered surface 58a of the deformable member layer 58 of the first deformed portion 50 is mirror finished and preferably the deformable member layer 58 of the second deformed portion 40 is anisotropic, More preferably, it is formed of any one material selected from quartz, MgF ₂ , or CdS.

Accordingly, in the light intensity adjusting apparatus according to the embodiment of the present invention shown in FIGS. 2 and 3, the laser beam emitted from the light source 20 is guided by the polarizing plate or the polarizing prism 22 in a predetermined direction (for example, 45 DEG), and the polarized light is incident on the polarization direction rotating member 24. In this case, when an electric field or a magnetic field is applied to the first and second electrodes 42 and 44 (52 and 54) of the first and second deformed parts 40 and 50 constituting the polarization direction rotating member 24 The piezoelectric material layers 46 and 56 interposed between the first and second electrodes 42 and 44 and 52 and 54 are expanded so that the first and second deformable portions 40 and 50 are deformed The member layers 48 and 58 are expanded in a direction in which the tapered surfaces 48a and 58a, which are mirror-finished, are mutually opposed in the gap portion (indicated by a dotted line in FIG. 4).

Therefore, the overall thickness d of the light compensating member 24 with respect to the light incident from the polarizing plate 24 is variable. In this case, in the polarization direction rotating member 24,

(Where n ₀ is a refractive index of ordinal axes and n _e is a refractive index of extraordinary axes).

When quartz is used as the anisotropic material constituting the variable member layers 48 and 58 of the polarization direction rotating member 24, the amount of rotation in the polarization direction per wavelength with respect to the wavelength is as shown in the following table.

Therefore, the rotation in the polarization direction The transmittance (T) of the light passing through the photometric plate or the light prism (28)

.

Therefore, the light transmitted through the polarization direction rotating member 24 is polarized at a constant angle relative to the time when it is emitted from the light source 20, and the polarized light or the polarizing prism 22 When a light-sensitive plate or a prism 26 having another polarizing direction (for example, + 45 °) is applied, the light with the polarization amount adjusted by the polarization direction rotating member 24 can be detected.

Here, when the light intensity control apparatus according to an embodiment of the present invention is applied to a projection type image display system such as a laser projector, the first and second deformed portions 40 and 50 of the polarization direction rotating member 24, A voltage corresponding to the image signal or an electric field or a magnetic field derived from the image signal voltage is applied to each of the first and second electrodes 42 and 44 .

FIG. 5 is a view for explaining the polarization direction rotating member of the light intensity adjusting apparatus according to another embodiment of the present invention. In the polarization direction rotating member 24 according to the embodiment of the present invention shown in FIG. 3, If the thickness d determined by the first and second deformations 40 and 50 does not approximate? / 2 from the formula of? =? /? D | _n0- n _e | (? I) of the transmission curve (a) shown in FIG. 6 when it is possible to obtain a sufficient permeability (I) as can be seen from the transmission curve (a) In order to prevent a sufficient optical modulation effect from being degraded due to a gentle change to a nonlinear region, in the present embodiment, sufficient light intensity change in a state in which the transmittance of light transmitted through the polarization direction rotating member 24 is shifted to the linear region In order to obtain a predetermined thickness, A polarization direction rotating member 24 'having a structure in which a board 90 is additionally provided is assumed.

That is, the polarization direction rotating member 24 'according to another embodiment of the present invention shown in FIG. 5 has the configuration of the polarization direction rotating member 24 according to the embodiment of the present invention described with reference to FIG. Similarly, the first and second deforming portions 70 and 80 are formed on the single base plate 60 so as to be compressed / expanded in mutually opposing directions in accordance with an electric field or a magnetic field.

The first and second deformations 70 and 80 may include first electrodes 72 and 82 and second electrodes 74 and 84 fixed on the single base plate 60 to which an electric field or a magnetic field is applied, A piezoelectric material having an expansion coefficient varying by an electric field or a magnetic field applied to the first and second electrodes 72, 74, 82, 84 interposed between the first and second electrodes 72, 74, And a variable member layer 78 88 formed so as to be tapered at one side surface 78a 88a of the first electrode 74 and the second electrode 74 to form a predetermined inclination angle. Each of the first electrodes 72 and 82 is fixed on the base plate 60 and applied as a common electrode while each of the second electrodes 74 and 84 is electrically insulated from the base plate 60 While being displaced in accordance with the contraction / expansion of the piezoelectric material layer (76; 86). The tapered surfaces 78a 88a of the variable member layers 78,88 of each of the first deformations 70,80 are mirror finished and are preferably mirror surfaces of the first and second deformations 70,80 The variable member layers 78 and 88 are formed of an anisotropic material, more preferably any one material selected from quartz, MgF ₂ , or CdS (i.e., a photoactive medium). An auxiliary panel 90 is formed at a rear end of the second deforming portion 80 to secure a projection degree in a linear region. The auxiliary panel 90 includes the first and second deforming portions 79 80 may be formed of a material having a different polarization rotation direction. That is, for example, when the medium constituting the first and second deforming portions has a left rotatory characteristic, the sub-panel 90 preferably has a drotrotatory characteristic.

Therefore, an effect similar to that of the above-described embodiment of the present invention is achieved by the polarization direction rotating member 24 'according to another embodiment of the present invention shown in FIG. 5, and further, (A) of the transmission curve (a) by the polarization action of the sub-panel 90 even when the thickness of the sub-panel (79; 80) is changed to approximate? / 2 in the transmission curve Can be obtained.

In addition, even when the light intensity control apparatus according to another embodiment of the present invention is applied to a projection type image display system such as a laser projector, the first and second deformations 70 and 80 of the light compensating member 24 ' The voltage corresponding to the image signal or an electric field or a magnetic field derived from the image signal voltage is applied to each of the first and second electrodes 72 and 74 Light can be obtained.

As described above, according to the light intensity adjusting apparatus of the present invention, since the light intensity is controlled by adjusting the rate of rotation of the piezoelectric material whose expansion ratio is varied by an electric field and the polarization direction of light transmitted through the piezoelectric material during expansion, The overall structure of the intensity adjusting device is simplified and the device can be manufactured at a relatively low cost.

Claims (11)

A polarizing means 22 for polarizing the light emitted from the light source 20 in a predetermined direction, a polarization direction rotating means 24 for rotating the polarization direction of the light polarized by the polarizing means 22 in a variable manner, (26) for focusing the light whose polarization direction is varied by the polarization direction rotating means (24). 2. The apparatus of claim 1, wherein the polarization direction rotating means (24) comprises first and second deformations (40; 50) formed to compress / expand in a direction opposite to each other according to an electric field or a magnetic field on a single base plate The first and second deformed portions 50 are formed on a single base plate 30 and are formed of a first electrode 42 and a second electrode 42 to which an electric field or a magnetic field is applied, 54 and the expansion ratio is set by the electric field or magnetic field applied to the first and second electrodes 42, 44, 52, 54 interposed between the first and second electrodes 42, And a variable member layer (48; 58) formed by being tapered on one side of the piezoelectric material layer (46; 56) and the second electrode (44; 54) Light intensity control device. 3. The method of claim 2, wherein the variable member layers (48; 58) of the first and second deformations (40; 50) are tapered such that mutually facing sides maintain a constant gap, and each variable member layer (48; 58) is mirror-finished. A light intensity modulation apparatus according to claim 2 or 3, wherein the variable member layers (48; 58) of the first and second deformations (40; 50) are formed of an anisotropic material. The optical intensity adjusting apparatus according to claim 4, wherein the anisotropic material forming the variable member layer (48; 58) is any one material selected from quartz, MgF ₂ , or CdS. A polarization means (22) for polarizing the light emitted from the light source (20) in a predetermined direction; and a control means for controlling the polarization direction of the light polarized by the polarization means (22) A polarization direction rotating means (24 ') provided with an auxiliary panel means (90) for compensating a rotation angle of the polarization direction when the polarization direction of the light is small, (26). ≪ / RTI > 7. The apparatus of claim 6, wherein the polarization direction rotating means (24 ') comprise first and second deformations (70) formed to compress / expand in a direction opposite to each other according to an electric field or a magnetic field on a single base plate (60). The first and second deformed portions 70 and 80 are formed on the single base plate 60 and include a first electrode 72 and a second electrode 72 to which an electric field or a magnetic field is applied, The electrodes 74 and 84 are disposed between the first and second electrodes 72 and 74 and are connected to the first and second electrodes 72 and 74 A piezoelectric material layer 76 having an expansion coefficient varying by the first electrode 74 and a variable electrode layer 78 formed by being tapered at one side of the second electrode 74 and formed to have a constant inclination angle Wherein the light intensity control device is characterized by: 8. The method of claim 7, wherein the variable member layers (78; 88) of the first and second deformations (70; 80) are tapered on opposite sides, And the surface is mirror-finished. The light intensity regulation device according to claim 7 or 8, wherein the variable member layers (78; 88) of the first and second deformations (70; 80) are formed of an anisotropic material. The method of claim 9, wherein the anisotropic material of the variable member layers (78; 88) of the first and second deformations (70; 80) is any one material selected from quartz, MgF ₂ , or CdS Light intensity control device. 7. The apparatus of claim 6, wherein the sub-panel means (90) is formed of a member having a different polarization rotation direction from the variable member layer (78; 88) of the first and second deformed portions (79; 80) Light intensity control device.