JP2011222461A - Transparent conductive film heater having temperature distribution equalizing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive transparent conductive film heater with high temperature distribution uniformity with good transparency, wide observing area and structural flexibility maintained, as a heater part used for controlling a temperature of equipment having a liquid crystal display, and equipment for observing a chemical reaction under a constant temperature.SOLUTION: A pair of parallel electrodes are manufactured by printing means using metallic paste provided on a transparent conductive film. One of the pair of the electrodes is made into upper and lower layers with an insulator interposed therebetween, and an electrical connecting point of the upper and lower layer electrodes is provided near an end that is furthest from a power source connection terminal, to which a power is supplied.

Description

  The present invention relates to a transparent and flexible film heater, and more particularly to an electrode structure and a shape of a transparent conductive film for making the temperature distribution on the heater surface uniform.

  The transparent conductive film heater is widely used for maintaining an object to be observed at an appropriate temperature, such as maintaining the liquid crystal display at an operating temperature, or controlling the temperature while observing a chemical reaction in the bottle. The flexibility of this transparent conductive film heater is an important characteristic for durability that allows it to be freely matched to the shape of the object to be observed and that can be used repeatedly.

  Conventionally, a transparent conductive film heater is formed by sputtering a transparent conductive film made of a metal oxide-based conductive material such as ITO or tin oxide on a film-like polymer base material such as PET or PEN. A pair of electrodes for supplying power was appropriately formed on both ends of the transparent conductive film. In order to maintain the flexibility of the heater and to reduce the cost, a metal paste in which a metal filler such as silver is mixed is used for the electrode.

JP2008-0778779 JP 2005-302553 A JP 8-138841 A JP-A-7-153559

Problems that the Invention is to Solve

  The metal paste used in transparent conductive film heaters contains organic resin with extremely low electrical conductivity, so the specific resistance value is higher than that of single metal, and the voltage drop at the electrode when the area resistance of the transparent conductive film is low. Has occurred, causing the problem that the observed object cannot be heated uniformly. The present invention discloses means for correcting this problem and preventing the uniformity of the temperature distribution on the heater surface.

Means for solving the problem

  In the present invention, five measures are taken in order to maintain the uniformity of the temperature distribution on the heater surface.

  As a first means, upper and lower two-layer electrodes are formed on one of a pair of electrodes printed with a metal paste via an insulating layer, and the upper and lower two-layer connection points are provided at the ends far from the power connection terminals of the electrodes. Structure.

  As a second means, in addition to the first means, in the transparent conductive film, slit-like conductive film removal grooves obtained by partially removing the conductive film perpendicular to the longitudinal direction of the electrodes are provided at equal intervals or unequal intervals. The structure is such that the direction of current flowing through the transparent conductive film is regulated to be perpendicular to the longitudinal direction of the electrode.

  As a third means, both of the pair of electrodes are formed as upper and lower two-layer electrodes via an insulating layer, and a connection point of upper and lower two layers is provided substantially at the center of the electrodes.

  As a fourth means, in addition to the third means, a transparent conductive film is provided with a slit-like conductive film removal groove perpendicular to the longitudinal direction of the electrode, and the groove width is changed depending on the location.

  As a fifth means, the fourth means is further improved, and as the distance from the connection point increases, the difference in the resistance value of the transparent conductive film in the distance between the electrodes per adjacent unit width including the conductive film removal groove increases in the longitudinal direction of the electrode. The conductive film removal groove has a structure that is equal to the resistance value per unit length.

  As a sixth means, in addition to the third, fourth and fifth means, the shape of the connection point of the upper and lower two-layer electrodes is a rectangle, the sides in the electrode width direction have the same length as the electrode width, The side is 1/5 or less of the electrode width.

The invention's effect

The transparent conductive film heater of the present invention has the following effects.
(1) While maintaining the maximum flexibility, the amount of current per unit area of the heater is uniform, and the variation in temperature distribution is extremely small.
(2) The display area of the display can be maximized by using two upper and lower electrodes.
(3) The printing method is used to form the electrode, and the manufacturing cost is low because the flexibility is maintained and the capital investment of the method is small.
(4) By providing the conductive film removal groove in the transparent conductive film, the uniformity of the temperature distribution can be further improved.
(5) By making both the pair of electrodes into a two-layer structure, the structure can be easily wrapped around the observation object.
(6) By positioning the connection point between the upper and lower electrodes in the center of the electrode, the increase in the resistance value of the electrode can be minimized and the balance of the voltage distribution at the connection point can be improved. Loss can also be reduced.

Illustration of prior art Explanatory drawing of Example 1 which made one side of the electrode into upper and lower two layers AA 'sectional view in FIG. Explanatory drawing when the aspect ratio of the transparent conductive film shape is increased in Example 1 Explanatory drawing of Example 2 which provided the electrically conductive film removal groove | channel in the transparent conductive film at equal intervals BB 'sectional view in FIG. Explanatory drawing of Example 3 which provided the connection point in the center of the upper and lower electrodes. CC 'sectional view in FIG. Explanatory drawing of Example 4 from which the width | variety of the electrically conductive film removal groove | channel provided in the transparent conductive film changes with places DD 'sectional view in FIG. Explanatory drawing of the prior art for demonstrating Example 5. FIG. EE 'sectional view of FIG. Explanatory drawing of the relationship between edge | side W4 of the width direction of a connection point, and edge | side L3 of an electrode longitudinal direction Explanatory drawing of lower layer electrode resistance of L3 and connection point edge part in FIG. Explanatory drawing of Example 5 regarding the shape of a connection point

  Here, the technical contents will be described in detail. FIG. 1 is a plan view of a conventionally used transparent conductive film heater. A metal paste in which a pair of parallel electrodes 10 and 11 are made of silver particles or the like is formed on a film of a polymer substrate 40 on which a transparent conductive film 30 such as ITO or tin oxide is formed by a thin film forming technique such as sputtering. And formed by printing means. A power connection terminal 20 for supplying power is provided at the end of the electrode. Prior to electrode printing, the transparent conductive film is shaped to be appropriately smaller than the polymer base material, and unnecessary portions are removed. In FIG. 1, the region where the electrode and the conductive film are in contact has a vertically symmetrical shape.

  In the transparent conductive film heater with this structure, when the area resistance of the transparent conductive film is low (20Ω / □ or less) or the aspect ratio is high (the shape is long horizontally or the distance between the upper and lower electrodes is small) The resistance value of the electrode becomes relatively larger than the resistance value of the transparent conductive film, and a voltage drop occurs from the power connection terminal of the electrode to the other end. As a result, a high temperature region 50 indicated by a dotted circle in FIG. 1 is generated, the temperature in a region far from the power supply connection terminal does not rise, and the temperature distribution is uneven across the heater surface.

  When such temperature distribution non-uniformity occurs, non-uniformity also occurs in the temperature of the object in contact with the transparent conductive film heater, making it difficult to keep the temperature constant. Alternatively, in the case of a bottle that causes a chemical reaction, temperature variation increases, making it impossible to conduct highly accurate experiments.

  In order to prevent such uneven temperature distribution, a method of forming a part or the whole of an electrode with a single metal has been proposed. That is, it is a method of forming a film of an electrode from a single metal using electron beam evaporation, sputtering, electrolytic plating, electroless plating, or the like. In this method, although the conductivity of the electrode is greatly increased, flexibility, which is an important characteristic of the transparent heater, is lost, durability during use is deteriorated, and expensive equipment is required as a film forming means.

  In the present invention, a metal paste printing means is used for the electrode manufacturing method, and the flexibility of the polymer base material is sufficiently maintained at a low cost, while the temperature of the object to be observed is maximized and the temperature is not uniform. The transparent conductive film film heater which prevented this is provided.

  First, in order to prevent non-uniform temperature distribution, the upper and lower electrodes are provided on the one end of the pair of electrodes with an upper and lower two layers through an insulating layer, and the upper and lower electrodes are electrically connected at the end farthest from the power connection terminal. . With such a structure, the sum of the resistance of the transparent conductive film and the resistance of the electrode at a distance between the electrodes per unit width as viewed from the power connection terminal 20 becomes constant. Therefore, the value of the flowing current is constant regardless of the location, and a uniform temperature distribution is obtained. In addition, the observation area of the object to be observed can be ensured to the maximum without changing even if there are two layers of electrodes.

  Even with such a structure, when the sheet resistance further decreases or the aspect ratio increases, the current is obliquely directed from the upper and lower two-layer connection point of the electrode toward the power supply connection terminal on the other side. A path is formed (FIG. 4). Naturally, temperature non-uniformity occurs on the heater surface. In order to prevent this, a slit-like groove from which a part of the conductive film is removed is provided in the transparent conductive film heater so that the current flow is regulated to be perpendicular to the longitudinal direction of the electrode.

  Furthermore, both the pair of electrodes (electrodes 11 and 10 in the structure of FIG. 1) are two layers in the upper and lower layers, and the connection point of the two layers is arranged in the center of the electrode in contact with the conductive film 30. If the electrode length is not larger than the distance between the electrodes (the width in the longitudinal direction of the conductive film), considerable temperature distribution uniformity can be achieved. Further, in the shape as shown in FIG. 1, since both the pair of electrodes have the same thickness, they can be properly wound around a bottle or the like. In addition, since the effective length of the electrode is reduced by about a quarter on average from the two-layer structure on only one side of the electrode, the power loss due to the resistance of the electrode is also halved.

  Thus, even when both of the pair of electrodes are upper and lower two layers and the connection point is in the center, when the area resistance of the transparent conductive film is low or the aspect ratio is high, the temperature at the end of the conductive film is A phenomenon of lowering occurs. Further, in order to prevent this, a structure in which the conductive film removal grooves in which the conductive film is removed perpendicularly to the electrode longitudinal direction as described above is provided at equal intervals or unequal intervals is employed. However, in this case, the groove width of the conductive film removal groove is different depending on the location. Specifically, by increasing the groove width near the center of the connection point, the sum of the resistance value of the electrode viewed from the power connection terminal and the conductive film per unit width is made approximately constant, and the current flow is made uniform. can do.

  In order to further improve the uniformity of the temperature, as the distance from the center line connecting the center of the connection point of the pair of electrodes provided in the center, the difference in the resistance value of the conductive film partitioned by the adjacent transparent conductive film removal grooves, The transparent electrode removal groove has a structure that matches the resistance value of the electrode per pitch. In this way, the resistance value partitioned by the transparent conductive film removal groove gradually decreases as the distance from the center line increases, so that current also flows through the conductive film end, and the temperature distribution on the conductive film surface is more accurately measured. Uniformity can be achieved.

  In a structure in which the position of the connection point is in the center of the electrode, w is equal to the electrode width, where w is the length of the connection point in the electrode width direction and L is the length of the connection point in the electrode longitudinal direction. A shape that is 1/5) · w is preferable. This relationship is obtained as a condition in which current flows to the left and right of the lower electrode through this connection point, and current is supplied at the same voltage in any direction. Therefore, if L increases (L> w), the left and right voltage balance at the electrode is lost, and the temperature distribution becomes non-uniform. Note that this is not the case in a structure in which the electrode is formed in two upper and lower layers on one side and the connection point is at the farthest end of the power connection terminal.

    FIG. 2 shows a first embodiment in which one of the pair of electrodes has two layers and the connection point of the electrodes is arranged at a position far from the power supply connection terminal 20. 3 is a cross-sectional view taken along the line AA ′ of FIG. In FIG. 2, the electrode disposed on the upper side has two layers, and the electrode is an upper layer electrode 11 and a lower layer electrode 12 in FIG. 3. FIG. 3 shows the structure of the connection point 60 in addition to the structure in which the electrode is formed into two layers through an insulating layer 70 made of resist. That is, a current is supplied to the lower layer electrode 12 via the connection point 60 between the upper and lower two layer electrodes. In this embodiment, the sum of the resistance of the transparent conductive film and the resistance of the electrode at a distance between the electrodes per unit width (resistance value viewed from the power connection terminal 20) is constant at any position in the transparent conductive film. Therefore, the current value per area in the transparent conductive film is constant, and the temperature distribution is uniform.

  On the other hand, even if one electrode has two layers, the observation area for visually observing the object to be observed can be ensured the maximum size as before. Note that the effect described so far does not change regardless of which of the upper and lower sides of the pair of electrodes is two layers.

  In Example 1, a uniform temperature distribution is obtained compared to the prior art, and an excellent transparent conductive film heater is obtained. However, when the aspect ratio is further increased and the resistance of the electrode is relatively increased, as shown in FIG. An oblique current path 80 is generated. For this reason, the current in places other than this current path is reduced, and the lower right side low temperature region S1 and the upper left side low temperature region S2 shown in FIG. 4 are generated. In order to prevent this, it is important to regulate the flow so that the current path is perpendicular to the longitudinal direction of the electrode.

  FIG. 5 shows a second embodiment in which this idea is embodied and the current path is restricted, and FIG. 6 is a sectional view taken along the line BB ′. In FIG. 5, slit-like conductive film removal grooves 90 having a groove width w1 and a groove length L1 are arranged at equal intervals. In this way, if the current is regulated so as to flow perpendicularly to the longitudinal direction of the electrode, the temperature distribution non-uniformity as shown in FIG. 4 can be prevented. In FIG. 5, the intervals between the conductive film removal grooves are equal. However, even if the intervals are not equal, the object can be achieved if the current is substantially perpendicular to the longitudinal direction of the electrode. The groove width is not necessarily the same.

  The conductive film removal grooves 90 shown in Example 2 are arranged with a width of about 100 μm and a pitch of about 10 mm. However, since the conductive film is transparent, it is difficult to visually confirm the grooves. Therefore, the conductive film removal groove does not cause inconvenience when observing the object to be observed.

  In FIG. 5, a continuous portion of the transparent conductive film of the upper continuous portion S3 and the lower continuous portion S4 is provided between the conductive film removal groove and the electrode, but this is not always necessary, and the groove is directly formed on the electrode. Even if the structure is in contact, the effect remains the same.

  The thicknesses of the electrodes 11 and 12 on the upper side in FIG. 2 of the first embodiment and the electrode 10 on the lower side are different from each other. The same applies to FIG. 5 of the second embodiment. In both embodiments, the length of the electrode for supplying power is longer than that of the conventional example, and power loss is generated accordingly. Naturally, it is necessary to reduce the length of the electrode as much as possible, and to reduce the extra power loss.

  From this point of view, these problems can be solved by forming the upper electrode and the lower electrode in two layers through an insulating layer and bringing the connection point to the center of the electrode. Example 3 of this consideration is shown in FIG. FIG. 8 is a cross-sectional view taken along the line CC ′ of FIG. 7 and 8, the upper layer electrode on the right side of the center line 64 that connects the connection point centers of the upper connection point 61 and the lower connection point 62 is a dummy in terms of electric circuit, so that the mechanical thickness is the same on the left and right. Is provided. By making the electrode thickness uniform, when it is wound around a bottle, it can be properly wound and the durability for repeated use is also improved.

  On the other hand, in this embodiment, the electrode length is reduced to 3/4 on average in comparison with the first and second embodiments, and the power loss due to the electrode is substantially halved. This half of the power loss leads to a reduction in voltage non-uniformity depending on the location of the electrode with respect to the transparent conductive film, and the non-uniform temperature distribution is alleviated. Further, since the voltage drop from the center line 64 to both ends in FIG. 7 is halved compared to the voltage drop from the power connection terminal side to the right end in FIG. 1 of the prior art, the uneven temperature distribution is further alleviated. Is done.

Example 4

  In Example 3, when the sheet resistance of the transparent conductive film decreases (20Ω / □ or less) or when the aspect ratio increases, the amount of current at the left and right ends of the transparent conductive film decreases, Nonuniform temperature distribution occurs at the end of the transparent conductive film 30 in FIG. In order to prevent this, it is considered that the width of the conductive film removal groove is changed depending on the location so that the total resistance value including the resistance in the longitudinal direction of the electrode becomes equal. Example 4 of this idea is shown in FIG. FIG. 10 is a sectional view taken along the line DD ′ of FIG. The basic idea is to make the width of the conductive film removal groove near the center line 64 larger than the groove width at the end.

Considering with further accuracy, in the plurality of conductive film removal grooves 90 provided in the transparent conductive film, the groove on the center line 64 is first, and then the width of the nth conductive film removal groove on the left and right is Wn, n + 1. The width of the second conductive film removal groove is Wn + 1. The length of the conductive film removal groove is L2. L2 is substantially equal to the distance between the electrodes. The arrangement pitch of the conductive film removal grooves is W0, the resistance value of the transparent conductive film at the distance between electrodes per pitch is R0, the resistance value in the longitudinal direction of the lower layer electrode corresponding to the pitch width is Rp, and the nth and n + 1th conductive films When the resistance value of the distance between the electrodes per pitch width of the transparent conductive film in contact with the removal groove is Rn, Rn + 1, Wn, Wn + 1 can be determined so that the following formula is established. First, the following relational expression holds.
Here, when considering that W0 << Wn, W0 << Wn + 1, the following expression is obtained.
If the width of the conductive film removal groove is formed in the transparent conductive film 30 so as to satisfy Equation 2, the voltage drop due to the electrodes is corrected, a uniform current density is maintained throughout the film, and a uniform temperature distribution is obtained. . Note that there are two n and n + 1, each having a center line as a symmetry line.

Here, a specific example of the contents of Equation 2 is shown. The sheet resistance value of the transparent conductive film is 20Ω / □ as a lower typical value, and the sheet resistance value of the silver paste electrode is 0.02Ω / □. If the electrode width is 0.5 cm (5 mm), the pitch W0 = 1 cm (10 mm) and Rp = 0.04Ω. When the distance between the electrodes of the transparent conductive film is 4 cm (40 mm), the resistance value per pitch of the transparent conductive film is R0 = 80Ω. Further, Equation 2 is calculated by substituting these values.

  That is, if the conductive film structure is such that the width of the groove is decreased by 5 μm per pitch as the conductive film removal groove is separated from the position of the center line 64 in FIG. Inevitably, the temperature distribution becomes uniform.

When the formation accuracy of the conductive film removal groove does not reach 5 μm, the object can be achieved by increasing and decreasing the width every time the number of grooves is increased to the formation accuracy with the pitch being constant in all the conductive films. For example, when the formation accuracy is 50 μm, this means that the groove width is reduced by 50 μm every time ten conductive film removal grooves are advanced.
Even when the width of the conductive film removal groove on the transparent conductive film becomes 0.3 mm or more which can be visually recognized, the conductive film removal groove becomes an obstacle to observing the object to be observed because it is originally transparent. There is no.

  FIG. 11 is an explanatory diagram of the prior art for explaining the fifth embodiment related to the enlarged connection point 63, and FIG. 12 is a cross-sectional view taken along the line EE ′ of FIG.

    The connection points shown in Example 3 of FIG. 7 and Example 4 of FIG. 9 are rectangular as shown in FIG. When the length of the side in the electrode width direction is W4 and the length of the side in the electrode longitudinal direction is represented by L3, in FIG. 11, W4 is narrower than W3, and L3 is approximately equal to or larger than W4. Yes.

  When the connection point is at the center of the electrode as shown in Examples 3 and 4, in the structure in which L3 is large as shown in FIG. 11 (L3 is approximately the same as the dimension of W3), the voltage drop at the connection point is small. As a result, the voltage of the electrode becomes asymmetrical in FIG. 11 and the amount of current decreases from the power source to the far side (right side). As a result, non-uniform current and non-uniform temperature distribution occur.

In order to prevent this non-uniformity, a shape with a small voltage drop at the connection point is considered. First, the resistance value Rw of the current path at the connection point of the electrode is calculated. The current path length at the connection point is equal to L3. In the connection point current path, there are a region where the thickness of the electrode is t of one layer and a region of thickness 2t which is two layers on the upper and lower sides. When the resistance value of the region having the thickness of 1 layer is Rw1, the resistance value of the region having the thickness of 1 layer is Rw2, and the specific resistance of the electrode is ρ0, the following equation is obtained.

On the other hand, the resistance RL when the current flows from the upper layer electrode to the lower layer electrode can be expressed by the following formula when the width of the resistance value calculation of the lower layer electrode is expressed as ΔL (about 1/100 cm order) as shown in FIGS. obtain.

  As a condition that no voltage drop occurs at the connection point, RL is equal to or smaller than Rw (RL ≦ Rw). Here, the thickness of the metal paste as the electrode material is 0.0025 cm, the electrode width W3 = 0.5 cm, and ΔL = 0.02 cm in consideration of printing accuracy, and the length of the side in the electrode width direction of the connection point While changing W4, the value of L3 where Rw = RL is obtained.

  FIG. 13 shows the value of L3 when W4 is changed from 0.005 cm to 0.5 cm. From FIG. 13, the value of L3 when Rw and RL are equal becomes smaller as W4 increases, and the maximum width W4 = W3 and the minimum L3 value is about 0.02 cm. FIG. 14 shows how the resistance value Rw (= RL) of the electrode current path at the connection point of the lower layer electrode 12 at this time changes. From FIG. 14, similarly to L3, the minimum value is obtained when W4 = W3, which is about 0.0004Ω.

  As can be seen from FIGS. 13 and 14, in order to reduce the left and right voltage drop at the electrode connection point and obtain a uniform temperature distribution, the side length W4 in the width direction of the connection point is equal to the electrode width W3. In addition, it can be seen that the length L3 of the connection point in the electrode direction should be as small as possible, and 1/10 or less as compared with W3. Here, since the printing accuracy of 0.02 cm is set as the resistance value calculation width ΔL of the connection point of the lower layer electrode, the length L3 of the side of the connection point in the electrode longitudinal direction is added as an error. 0.02 + 2 · ΔL = 0.06 cm. In conclusion, it is desirable that the electrode width is approximately 1/5 or less compared to the electrode width of 0.5 cm. FIG. 15 shows an optimum planar shape of the approximate connection point in the fifth embodiment.

  If there is a connection point at the center of the upper electrode and the lower electrode as in Examples 3 and 4, it is better to use a vertically long rectangular connection point shape as a result of this consideration, This is not the case when the connection point is not the center as in Examples 1 and 2. However, in any of the embodiments, it is preferable that the length W4 of the side in the width direction of the connection point and the width W3 of the electrode coincide within an error range.

Industrial applicability

  Temperature control device for display of measuring instrument used under constant temperature, temperature control device for liquid crystal display in camera, video equipment and mobile phone, observation device for tablet dissolution process in heated aqueous solution in new drug development and addition of infusion in treatment There is a possibility of adaptation to temperature devices.

DESCRIPTION OF SYMBOLS 10 Electrode 11 Upper layer electrode 12 Lower layer electrode 20 Power supply connection terminal 30 Transparent conductive film 40 Polymer substrate 50 High temperature region 60 Connection point 61 Upper connection point 62 Lower connection point 63 Expanded connection point 64 Center line 70 Insulating layer (resist)
71 Insulating layer 80 of fifth embodiment Diagonal current path 90 Conductive film removal groove

S1 Lower right side low temperature region S2 Upper left side low temperature region S3 Upper continuous portion S4 Lower continuous portion L Length of connection point L1 in the longitudinal direction of the electrode L1 Length of groove L2 Length of the conductive film removal groove L3 Side of the connection point in the longitudinal direction of the electrode Length ΔL Width of calculation of resistance value of lower layer electrode at connection point ρ0 Specific resistance of electrode R0 Resistance value of distance between electrodes at pitch width of transparent conductive film RL Resistance at which current flows into lower layer electrode of connection point edge Rn n The resistance value Rn + 1 of the transparent conductive film at the distance between the electrodes per pitch width in contact with the first conductive film removal groove The resistance value Rp of the transparent conductive film at the distance between the electrodes per pitch width in contact with the nth conductive film removal groove Rp Resistance value Rw of pitch length Resistance value Rw1 of electrode current path at connection point Resistance value of only one layer of electrode current path at connection point (width: W3-W4)
Rw2 Resistance value of two layers of electrode current path at connection point (width: W4)
t electrode thickness W connection point width W0 conductive film removal groove arrangement pitch W1 groove width W3 electrode width W4 connection point width Wn nth conductive film removal groove width Wn + 1 n + 1th conductive film removal groove width

Claims (6)

  In a structure in which a transparent conductive film to be a heater is formed on a transparent and flexible polymer substrate, and a pair of electrodes made of a metal paste for supplying power is provided thereon, one of the electrodes is insulated. A transparent conductive film heater having two upper and lower layers through layers and having a connection point that enables electrical conduction between the upper and lower layers in the vicinity of the end farthest from the terminal for supplying power.   The transparent conductive film is provided with slit-like conductive film removal grooves at equal or non-uniform intervals perpendicular to the longitudinal direction of the pair of electrodes and having a width larger than the manufacturing accuracy and approximately equal to the distance between the pair of electrodes. The transparent conductive film film heater according to claim 1.   In a structure in which a transparent conductive film to be a heater is formed on a transparent and flexible polymer base material and a pair of electrodes made of a metal paste for supplying power is provided thereon, both of the pair of electrodes are insulated. A transparent conductive film heater having two upper and lower layers through layers, and a connection point that enables electrical conduction in each of the electrodes.   The straight line connecting the centers of the connection points provided at the center of the pair of electrodes is set as the center line, and the groove width gradually decreases as the distance from the center line increases, and the width of the groove is equal or uneven. 4. The transparent conductive film heater according to claim 3, further comprising a conductive film removal groove perpendicular to the longitudinal direction. The conductive film removal groove on the center line extending in the vertical direction is the first, and the groove numbers are sequentially assigned to the left and right as the distance from the center line increases. The groove width of the nth groove is Wn, and the groove width of the (n + 1) th groove is Wn + 1. When the width of one pitch is W0, the resistance value of the pitch length in the longitudinal direction of one electrode is Rp, and the resistance value of the transparent conductive film having the pitch width and the distance between the electrodes is R0,
Wn−Wn + 1 = W0 · Rp / R0
The transparent conductive film heater according to claim 4, wherein the conductive film removal groove has a groove width structure that satisfies the following relationship.   When the width of the pair of electrodes is W3, the length of the side in the electrode width direction of the rectangular connection point provided at the center of the electrode is W4, and the length of the side in the electrode longitudinal direction is L3, W4 = W3 The transparent conductive film heater according to claim 3, 4, or 5, wherein L3 ≦ (1/5) · W3.